Microbial air quality and bacterial surface contamination in ambulances during patient services.

Science.gov (United States)

Luksamijarulkul, Pipat; Pipitsangjan, Sirikun

2015-03-01

We sought to assess microbial air quality and bacterial surface contamination on medical instruments and the surrounding areas among 30 ambulance runs during service. We performed a cross-sectional study of 106 air samples collected from 30 ambulances before patient services and 212 air samples collected during patient services to assess the bacterial and fungal counts at the two time points. Additionally, 226 surface swab samples were collected from medical instrument surfaces and the surrounding areas before and after ambulance runs. Groups or genus of isolated bacteria and fungi were preliminarily identified by Gram's stain and lactophenol cotton blue. Data were analyzed using descriptive statistics, t-test, and Pearson's correlation coefficient with a p-value of less than 0.050 considered significant. The mean and standard deviation of bacterial and fungal counts at the start of ambulance runs were 318±485cfu/m(3) and 522±581cfu/m(3), respectively. Bacterial counts during patient services were 468±607cfu/m(3) and fungal counts were 656±612cfu/m(3). Mean bacterial and fungal counts during patient services were significantly higher than those at the start of ambulance runs, p=0.005 and p=0.030, respectively. For surface contamination, the overall bacterial counts before and after patient services were 0.8±0.7cfu/cm(2) and 1.3±1.1cfu/cm(2), respectively (pair samples and bacterial counts on medical instruments and allocated areas. This study revealed high microbial contamination (bacterial and fungal) in ambulance air during services and higher bacterial contamination on medical instrument surfaces and allocated areas after ambulance services compared to the start of ambulance runs. Additionally, bacterial and fungal counts in ambulance air showed a significantly positive correlation with the bacterial surface contamination on medical instruments and allocated areas. Further studies should be conducted to determine the optimal intervention to reduce

Geostatistical integration and uncertainty in pollutant concentration surface under preferential sampling

Directory of Open Access Journals (Sweden)

Laura Grisotto

2016-04-01

Full Text Available In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main interest in statistical integration and uncertainty. We used PM10 data arising from the air quality network of the Environmental Protection Agency of Lombardy Region (Italy and numerical outputs from the deterministic model. We specified an inhomogeneous Poisson process for the sampling locations intensities and a shared spatial random component model for the dependence between the spatial location of monitors and the pollution surface. We found greater predicted standard deviation differences in areas not properly covered by the air quality network. In conclusion, in this context inferences on prediction uncertainty may be misleading when geostatistical modelling does not take into account preferential sampling.

Environmental survey to assess viral contamination of air and surfaces in hospital settings.

Science.gov (United States)

Carducci, A; Verani, M; Lombardi, R; Casini, B; Privitera, G

2011-03-01

The presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (air was 282 cfu/m(3). Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment. Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

40 CFR 61.34 - Air sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Air sampling. 61.34 Section 61.34... sampling. (a) Stationary sources subject to § 61.32(b) shall locate air sampling sites in accordance with a... concentrations calculated within 30 days after filters are collected. Records of concentrations at all sampling...

Air sampling with solid phase microextraction

Science.gov (United States)

Martos, Perry Anthony

There is an increasing need for simple yet accurate air sampling methods. The acceptance of new air sampling methods requires compatibility with conventional chromatographic equipment, and the new methods have to be environmentally friendly, simple to use, yet with equal, or better, detection limits, accuracy and precision than standard methods. Solid phase microextraction (SPME) satisfies the conditions for new air sampling methods. Analyte detection limits, accuracy and precision of analysis with SPME are typically better than with any conventional air sampling methods. Yet, air sampling with SPME requires no pumps, solvents, is re-usable, extremely simple to use, is completely compatible with current chromatographic equipment, and requires a small capital investment. The first SPME fiber coating used in this study was poly(dimethylsiloxane) (PDMS), a hydrophobic liquid film, to sample a large range of airborne hydrocarbons such as benzene and octane. Quantification without an external calibration procedure is possible with this coating. Well understood are the physical and chemical properties of this coating, which are quite similar to those of the siloxane stationary phase used in capillary columns. The log of analyte distribution coefficients for PDMS are linearly related to chromatographic retention indices and to the inverse of temperature. Therefore, the actual chromatogram from the analysis of the PDMS air sampler will yield the calibration parameters which are used to quantify unknown airborne analyte concentrations (ppb v to ppm v range). The second fiber coating used in this study was PDMS/divinyl benzene (PDMS/DVB) onto which o-(2,3,4,5,6- pentafluorobenzyl) hydroxylamine (PFBHA) was adsorbed for the on-fiber derivatization of gaseous formaldehyde (ppb v range), with and without external calibration. The oxime formed from the reaction can be detected with conventional gas chromatographic detectors. Typical grab sampling times were as small as 5 seconds

Apparatus for surface treatment of U-Pu carbide fuel samples

International Nuclear Information System (INIS)

Fukushima, Susumu; Arai, Yasuo; Handa, Muneo; Ohmichi, Toshihiko; Shiozawa, Ken-ichi.

1979-05-01

Apparatus has been constructed for treating the surface of U-Pu carbide fuel samples for EPMA. The treatment is to clean off oxide layer on the surface, then coat with an electric-conductive material. The apparatus, safe in handling plutonium, operates as follows. (1) To avoid oxidation of the analyzing surface by oxygen and water in the air, series of cleaning and coating, i.e. ion-etching and ion-coating or ion-etching and vacuum-evaporation is done at the same time in an inert gas atmosphere. (2) Ion-etching is possible on samples embedded in non-electric-conductive and low heat-conductive resin. (3) Since the temperature rise in (2) is negligible, there is no deterioration of the samples. (author)

Dynamic air layer on textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev

2013-09-03

We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

Isopleths of surface air concentration and surface air kerma rate due to a radioactive cloud released from a stack (3)

International Nuclear Information System (INIS)

Tachibana, Haruo; Kikuchi, Masamitsu; Sekita, Tsutomu; Yamaguchi, Takenori

2004-06-01

This report is a revised edition of 'Isopleths of Surface Air Concentration and Surface Air Absorbed Dose Rate due to a Radioactive Cloud Released from a Stack(II) '(JAERI-M 90-206) and based on the revised Nuclear Safety Guidelines reflected the ICRP1990 Recommendation. Characteristics of this report are the use of Air Karma Rate (Gy/h) instead of Air Absorbed Dose Rate (Gy/h), and the record of isopleths of surface air concentration and surface air karma rate on CD-ROM. These recorded data on CD-ROM can be printed out on paper and/or pasted on digital map by personal computer. (author)

Colonization by Cladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

Science.gov (United States)

Ahearn, D. G.; Simmons, R. B.; Switzer, K. F.; Ajello, L.; Pierson, D. L.

1991-01-01

Cladosporium cladosporioides and C. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.

Air sampling system for airborne surveys

International Nuclear Information System (INIS)

Jupiter, C.; Tipton, W.J.

1975-01-01

An air sampling system has been designed for installation on the Beechcraft King Air A-100 aircraft as a part of the Aerial Radiological Measuring System (ARMS). It is intended for both particle and whole gas sampling. The sampling probe is designed for isokinetic sampling and is mounted on a removable modified escape hatch cover, behind the co-pilot's seat, and extends about two feet forward of the hatch cover in the air stream lines. Directly behind the sampling probe inside the modified hatch cover is an expansion chamber, space for a 5-inch diameter filter paper cassette, and an optional four-stage cascade impactor for particle size distribution measurements. A pair of motors and blower pumps provide the necessary 0.5 atmosphere pressure across the type MSA 1106 B glass fiber filter paper to allow a flow rate of 50 cfm. The MSA 1106 B filter paper is designed to trap sub-micrometer particles with a high efficiency; it was chosen to enable a quantitative measurement of airborne radon daughters, one of the principal sources of background signals when radiological surveys are being performed. A venturi section and pressure gauges allow air flow rate measurements so that airborne contaminant concentrations may be quantified. A whole gas sampler capable of sampling a cubic meter of air is mounted inside the aircraft cabin. A nuclear counting system on board the aircraft provides capability for α, β and γ counting of filter paper samples. Design data are presented and types of survey missions which may be served by this system are described

Ram-air sample collection device for a chemical warfare agent sensor

Science.gov (United States)

Megerle, Clifford A.; Adkins, Douglas R.; Frye-Mason, Gregory C.

2002-01-01

In a surface acoustic wave sensor mounted within a body, the sensor having a surface acoustic wave array detector and a micro-fabricated sample preconcentrator exposed on a surface of the body, an apparatus for collecting air for the sensor, comprising a housing operatively arranged to mount atop the body, the housing including a multi-stage channel having an inlet and an outlet, the channel having a first stage having a first height and width proximate the inlet, a second stage having a second lower height and width proximate the micro-fabricated sample preconcentrator, a third stage having a still lower third height and width proximate the surface acoustic wave array detector, and a fourth stage having a fourth height and width proximate the outlet, where the fourth height and width are substantially the same as the first height and width.

Study on sampling conditions for the monitoring of waste air

International Nuclear Information System (INIS)

Moeller, T.J.; Buetefisch, K.A.

1998-01-01

The technical codes for radiological monitoring of the waste air released from a radwaste repository demand that sampling for determination of aerosol-borne radioactivity is to be made with a screener equipped with a suitable number of measuring probes extending over the entire cross-sectional surface of the vent. Another requirement is to ensure that the waste air stream passing through the measuring channel is representative, containing the typical, operation-induced distribution of aerosols across the surface to be scanned. The study reported was intended to determine in a scaled-down model (1:10) of a repository ventilating duct the typical spatial distribution of aerosols (3D particulate density) in order to establish information on the type of typical distributions of aerosols, to be used for optimisation of the measuring site and monitoring instruments. (orig./CB) [de

A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air

International Nuclear Information System (INIS)

Zhang Yuzhong; Deng Shuxing; Liu Yanan; Shen Guofeng; Li Xiqing; Cao Jun; Wang Xilong; Reid, Brian; Tao Shu

2011-01-01

Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAH LMW4 ) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAH LMW4 within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. - Research highlights: → Design, field test and calibration of the novel passive air sampler, PAS-V-I. → Vertical concentration gradients of PAH LMW4 within a thin layer close to soil. → Comparison of results between PAS-V-I measurement and fugacity approach. → Potential application of PAS-V-I and further modifications. - A novel passive sampling device was developed and tested for measuring vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air.

Operational air sampling report, July--December 1991

International Nuclear Information System (INIS)

Lyons, C.L.

1992-11-01

Air sampling is one of the more useful ways of assessing the effectiveness of operational radiation safety programs at the Nevada Test Site (NTS). Air sampling programs document NTS airborne radionuclide concentrations in various work locations and environments. These concentrations generally remain well below the Derived Air Concentration (DAC) values prescribed by the Department of Energy (DOE 5480.11, Attachment 1) or the Derived Concentration Guide (DCG) values prescribed by the Department of Energy DOE 5400.5, Chapter Ill. The Defense Nuclear Agency (DNA) tunnel complexes, Area 12 Test Support Compound and the Area 6 Decontamination Pad and Laundry air sampling programs are summarized in this report. Evaluations are based on Analytical Services Department (ASD) Counting Laboratory analyses and Health Protection Department (HPD)/Radiological Field Operations Section (RFOS) radiation protection technician's (RPT) or health physicists' calculations for air samples collected July 1 through December 31, 1991. Of the NTS operational air sampling programs in the tunnel complexes, the initial mining and event reentry and recovery operations represent the only real airborne radioactive inhalation potentials to personnel. Monthly filter and scintillation cell samples were taken and counted in RDA-200 Radon Detectors to document working levels of radon/thoron daughters and picocurie/liter (PCVL) concentrations of radon gas. Weekly Drierite samples for tritium analysis were taken in the active tunnel complexes to document any changes in normal background levels or reentry drifts as they are advanced toward ground zero (GZ) areas. Underground water sources are considered primary transporters of tritium from old event areas

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study.

Science.gov (United States)

Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D'Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

2017-06-22

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis ® μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis ® μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis ® μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis ® μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study

Science.gov (United States)

Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D’Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

2017-01-01

Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations. PMID:28640202

Preservation of atomically clean silicon surfaces in air by contact bonding

DEFF Research Database (Denmark)

Grey, Francois; Ljungberg, Karin

1997-01-01

When two hydrogen-passivated silicon surfaces are placed in contact under cleanroom conditions, a weak bond is formed. Cleaving this bond under ultrahigh vacuum (UHV) conditions, and observing the surfaces with low energy electron diffraction and scanning tunneling microscopy, we find that the or...... reconstruction from oxidation in air, Contact bonding opens the way to novel applications of reconstructed semiconductor surfaces, by preserving their atomic structure intact outside of a UHV chamber. (C) 1997 American Institute of Physics.......When two hydrogen-passivated silicon surfaces are placed in contact under cleanroom conditions, a weak bond is formed. Cleaving this bond under ultrahigh vacuum (UHV) conditions, and observing the surfaces with low energy electron diffraction and scanning tunneling microscopy, we find...... that the ordered atomic structure of the surfaces is protected from oxidation, even after the bonded samples have been in air for weeks. Further, we show that silicon surfaces that have been cleaned and hydrogen-passivated in UHV can be contacted in UHV in a similarly hermetic fashion, protecting the surface...

Directional dependency of air sampling

International Nuclear Information System (INIS)

1994-01-01

A field study was performed by Idaho State University-Environmental Monitoring Laboratory (EML) to examine the directional dependency of low-volume air samplers. A typical continuous low volume air sampler contains a sample head that is mounted on the sampler housing either horizontally through one of four walls or vertically on an exterior wall 'looking down or up.' In 1992, a field study was undertaken to estimate sampling error and to detect the directional effect of sampler head orientation. Approximately 1/2 mile downwind from a phosphate plant (continuous source of alpha activity), four samplers were positioned in identical orientation alongside one sampler configured with the sample head 'looking down'. At least five consecutive weekly samples were collected. The alpha activity, beta activity, and the Be-7 activity collected on the particulate filter were analyzed to determine sampling error. Four sample heads were than oriented to the four different horizontal directions. Samples were collected for at least five weeks. Analysis of the alpha data can show the effect of sampler orientation to a know near source term. Analysis of the beta and Be-7 activity shows the effect of sampler orientation to a ubiquitous source term

Surface Flux Modeling for Air Quality Applications

Directory of Open Access Journals (Sweden)

Limei Ran

2011-08-01

Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

Active AirCore Sampling: Constraining Point Sources of Methane and Other Gases with Fixed Wing Unmanned Aerial Systems

Science.gov (United States)

Bent, J. D.; Sweeney, C.; Tans, P. P.; Newberger, T.; Higgs, J. A.; Wolter, S.

2017-12-01

Accurate estimates of point source gas emissions are essential for reconciling top-down and bottom-up greenhouse gas measurements, but sampling such sources is challenging. Remote sensing methods are limited by resolution and cloud cover; aircraft methods are limited by air traffic control clearances, and the need to properly determine boundary layer height. A new sampling approach leverages the ability of unmanned aerial systems (UAS) to measure all the way to the surface near the source of emissions, improving sample resolution, and reducing the need to characterize a wide downstream swath, or measure to the full height of the planetary boundary layer (PBL). The "Active-AirCore" sampler, currently under development, will fly on a fixed wing UAS in Class G airspace, spiraling from the surface to 1200 ft AGL around point sources such as leaking oil wells to measure methane, carbon dioxide and carbon monoxide. The sampler collects a 100-meter long sample "core" of air in an 1/8" passivated stainless steel tube. This "core" is run on a high-precision instrument shortly after the UAS is recovered. Sample values are mapped to a specific geographic location by cross-referencing GPS and flow/pressure metadata, and fluxes are quantified by applying Gauss's theorem to the data, mapped onto the spatial "cylinder" circumscribed by the UAS. The AirCore-Active builds off the sampling ability and analytical approach of the related AirCore sampler, which profiles the atmosphere passively using a balloon launch platform, but will add an active pumping capability needed for near-surface horizontal sampling applications. Here, we show design elements, laboratory and field test results for methane, describe the overall goals of the mission, and discuss how the platform can be adapted, with minimal effort, to measure other gas species.

Air Monitoring: New Advances in Sampling and Detection

Directory of Open Access Journals (Sweden)

Nicola Watson

2011-01-01

Full Text Available As the harmful effects of low-level exposure to hazardous organic air pollutants become more evident, there is constant pressure to improve the detection limits of indoor and ambient air monitoring methods, for example, by collecting larger air volumes and by optimising the sensitivity of the analytical detector. However, at the other end of the scale, rapid industrialisation in the developing world and growing pressure to reclaim derelict industrial land for house building is driving the need for air monitoring methods that can reliably accommodate very-high-concentration samples in potentially aggressive matrices. This paper investigates the potential of a combination of two powerful gas chromatography—based analytical enhancements—sample preconcentration/thermal desorption and time-of-flight mass spectrometry—to improve quantitative and qualitative measurement of very-low-(ppt level organic chemicals, even in the most complex air samples. It also describes new, practical monitoring options for addressing equally challenging high-concentration industrial samples.

The NYC native air sampling pilot project: using HVAC filter data for urban biological incident characterization.

Science.gov (United States)

Ackelsberg, Joel; Leykam, Frederic M; Hazi, Yair; Madsen, Larry C; West, Todd H; Faltesek, Anthony; Henderson, Gavin D; Henderson, Christopher L; Leighton, Terrance

2011-09-01

Native air sampling (NAS) is distinguished from dedicated air sampling (DAS) devices (eg, BioWatch) that are deployed to detect aerosol disseminations of biological threat agents. NAS uses filter samples from heating, ventilation, and air conditioning (HVAC) systems in commercial properties for environmental sampling after DAS detection of biological threat agent incidents. It represents an untapped, scientifically sound, efficient, widely distributed, and comparably inexpensive resource for postevent environmental sampling. Calculations predict that postevent NAS would be more efficient than environmental surface sampling by orders of magnitude. HVAC filter samples could be collected from pre-identified surrounding NAS facilities to corroborate the DAS alarm and delineate the path taken by the bioaerosol plume. The New York City (NYC) Native Air Sampling Pilot Project explored whether native air sampling would be acceptable to private sector stakeholders and could be implemented successfully in NYC. Building trade associations facilitated outreach to and discussions with property owners and managers, who expedited contact with building managers of candidate NAS properties that they managed or owned. Nominal NAS building requirements were determined; procedures to identify and evaluate candidate NAS facilities were developed; data collection tools and other resources were designed and used to expedite candidate NAS building selection and evaluation in Manhattan; and exemplar environmental sampling playbooks for emergency responders were completed. In this sample, modern buildings with single or few corporate tenants were the best NAS candidate facilities. The Pilot Project successfully demonstrated that in one urban setting a native air sampling strategy could be implemented with effective public-private collaboration.

Sources of present Chernobyl-derived caesium concentrations in surface air and deposition samples

International Nuclear Information System (INIS)

Hoetzl, H.; Rosner, G.; Winkler, R.; Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg

1992-01-01

The sources of Chernobyl-derived caesium concentrations in air and deposition samples collected from mid-1986 to end-1990 at Munich- Neuherberg, Germany, were investigated. Local resuspension has been found to be the main source. By comparison with deposition data from other locations it is estimated that within a range from 20 Bq m -2 to 60 kBq m -2 of initially deposited 137 Cs activity ∼2% is re-deposited by the process of local resuspension in Austria, Germany, Japan and United Kingdom, while significantly higher total resuspension is to be expected for Denmark and Finland. Stratospheric contribution to present concentrations is shown to be negligible. This is confirmed by cross correlation analysis between the time series of 137 Cs in air and precipitation before and after the Chernobyl accident and the respective time series of cosmogenic 7 Be, which is an indicator of stratospheric input. Seasonal variations of caesium concentrations with maxima in winter were observed. (author). 32 refs.; 5 figs.; 1 tab

Plutonium isotopes in the surface air in Japan

International Nuclear Information System (INIS)

Hirose, K.; Sugimura, Y.

1990-01-01

Plutonium isotope concentrations in the surface air at Tsukuba, Japan are reported during the period from 1981 to the end of 1986. The 239,240 Pu concentration in the surface air, which showed a marked seasonal variation with a spring maximum and fall minimum, decreased until the end of 1985 according to the stratospheric residence time of 1.15 years. In May 1986, elevated 239,240 Pu concentrations with high 238 Pu/ 239,240 Pu activity ratios were observed. The serial trend of plutonium concentration in the surface air is similar to the concentrations of the Chernobyl-released radionuclides. These findings suggest that a significant part of the plutonium in the surface air in May 1986 was due to the Chernobyl fallout. (author) 15 refs.; 2 figs.; 3 tabs

Air exposure and sample storage time influence on hydrogen release from tungsten

Energy Technology Data Exchange (ETDEWEB)

Moshkunov, K.A., E-mail: moshkunov@gmail.co [National Research Nuclear University ' MEPhI' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Schmid, K.; Mayer, M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Kurnaev, V.A.; Gasparyan, Yu.M. [National Research Nuclear University ' MEPhI' , Kashirskoe sh. 31, 115409 Moscow (Russian Federation)

2010-09-30

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D{sub 2}O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of {approx}300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

Air exposure and sample storage time influence on hydrogen release from tungsten

International Nuclear Information System (INIS)

Moshkunov, K.A.; Schmid, K.; Mayer, M.; Kurnaev, V.A.; Gasparyan, Yu.M.

2010-01-01

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D 2 O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of ∼300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

Air exposure and sample storage time influence on hydrogen release from tungsten

Science.gov (United States)

Moshkunov, K. A.; Schmid, K.; Mayer, M.; Kurnaev, V. A.; Gasparyan, Yu. M.

2010-09-01

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D 2O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of ˜300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.

A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air.

Science.gov (United States)

Zhang, Yuzhong; Deng, Shuxing; Liu, Yanan; Shen, Guofeng; Li, Xiqing; Cao, Jun; Wang, Xilong; Reid, Brian; Tao, Shu

2011-03-01

Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAH(LMW4)) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAH(LMW4) within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. Copyright © 2010 Elsevier Ltd. All rights reserved.

Operational air sampling report, January--June 30, 1992

International Nuclear Information System (INIS)

Lyons, C.L.

1992-09-01

Nevada Test Site postshot and tunnel events generate beta/gamma fission products. The Reynolds Electrical ampersand Engineering Co., Inc. air sampling program is designed for measurement of these radionuclides at various facilities supporting these events. Monthly radon sampling is done for documentation of working levels in the tunnel complexes, which would be expected to hove the highest radon levels for on-site facilities. Out of a total of 281 air samples taken in the tunnel complexes, 25 showed airborne fission products with concentrations well below their respective Derived Air Concentrations (DAC). All of these were related to event reentry or mineback operations. Tritiated water vapor and radon levels were very similar to previously reported levels. The 975 air samples taken at the Area-6 decontamination bays and laundry were again well below any DAC calculation standard and negative for any airborne fission products from laboratory analyses

Printed Self-Powered Miniature Air Sampling Sensors

Directory of Open Access Journals (Sweden)

Joseph Birmingham

2017-07-01

Full Text Available The recent geo-political climate has increased the necessity for autonomous, chip-sized, lightweight, air sampling systems which can quickly detect and characterize chemical, biological, radiological, nuclear, and high explosive (CBRNE hazardous materials and relay the results. To address these issues, we have developed a self-powered 3-D chip architecture that processes air to produce concentrated size- sorted particle (and vapor samples that could be integrated with on-chip nanoelectronic detectors for the discovery of weapons of mass destruction (WMD. The unique air movement approach is composed of a nanoscale energy harvester that provides electricity to a printed ion-drag pump to push air through coated-microstructured arrays. The self-powered microstructured array air sampler was designed using computational fluid dynamics (CFD modeling to collect particles from 1-10 microns at greater than 99.9999 % efficiency with less than 100 Pascal [Pa] pressure drop at a specified air flow rate. Surprisingly, even at minimum air flow rates below specifications, these CFD predictions were matched by experimental results gathered in a Government aerosol chamber. The microstructured array engineered filter equaled the collection capability of a membrane or a high efficiency particle air (HEPA filter at a fraction of the filter pressure drop.

Sources of present Chernobyl-derived caesium concentrations in surface air and deposition samples

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, H.; Rosner, G.; Winkler, R. (Gesellschaft fuer Strahlen-und Umweltforschung Munich, Neuherberg (Germany). Forschungszentrum fuer Umwelt und Gesundheit Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany). Inst. fuer Strahlenschutz)

1992-06-01

The sources of Chernobyl-derived caesium concentrations in air and deposition samples collected from mid-1986 to end-1990 at Munich- Neuherberg, Germany, were investigated. Local resuspension has been found to be the main source. By comparison with deposition data from other locations it is estimated that within a range from 20 Bq m[sup -2] to 60 kBq m[sup -2] of initially deposited [sup 137]Cs activity [approx]2% is re-deposited by the process of local resuspension in Austria, Germany, Japan and United Kingdom, while significantly higher total resuspension is to be expected for Denmark and Finland. Stratospheric contribution to present concentrations is shown to be negligible. This is confirmed by cross correlation analysis between the time series of [sup 137]Cs in air and precipitation before and after the Chernobyl accident and the respective time series of cosmogenic [sup 7]Be, which is an indicator of stratospheric input. Seasonal variations of caesium concentrations with maxima in winter were observed. (author). 32 refs.; 5 figs.; 1 tab.

Morphing Surfaces Enable Acoustophoretic Contactless Transport of Ultrahigh-Density Matter in Air

Science.gov (United States)

Foresti, Daniele; Sambatakakis, Giorgio; Bottan, Simone; Poulikakos, Dimos

2013-01-01

The controlled contactless transport of heavy drops and particles in air is of fundamental interest and has significant application potential. Acoustic forces do not rely on special material properties, but their utility in transporting heavy matter in air has been restricted by low power and poor controllability. Here we present a new concept of acoustophoresis, based on the morphing of a deformable reflector, which exploits the low reaction forces and low relaxation time of a liquid with enhanced surface tension through the use of thin overlaid membrane. An acoustically induced, mobile deformation (dimple) on the reflector surface enhances the acoustic field emitted by a line of discretized emitters and enables the countinuos motion of heavy levitated samples. With such interplay of emitters and reflecting soft-structure, a 5 mm steel sphere (0.5 grams) was contactlessly transported in air solely by acoustophoresis. PMID:24212104

Determination of plutonium in air and smear samples

International Nuclear Information System (INIS)

Hinton, E.R. Jr.; Tucker, W.O.

1981-01-01

A method has been developed for the determination of plutonium in air samples and smear samples that were collected on filter papers. The sample papers are digested in nitric acid, extracted into 2-thenoyltrifluoroacetone (TTA)-xylene, and evaporated onto stainless steel disks. Alpha spectrometry is employed to determine the activity of each plutonium isotope. Each sample is spiked with plutonium-236. All glassware used in the procedure is disposable. The detection limits are 3 and 5 dpm (disintegrations per minute) for air and smear samples, respectively, with an average recovery of 87%

Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

International Nuclear Information System (INIS)

Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

2009-01-01

Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6 - 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

International Nuclear Information System (INIS)

Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

2008-01-01

Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6- 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

International Nuclear Information System (INIS)

Liu Chaozong; Cui Naiyi; Osbeck, Susan; Liang He

2012-01-01

Highlights: ► PMMA micro-beads were processed using a rotary air plasma reactor. ► Surface chemistry and surface texture of PMMA micro-beads were characterised. ► Surface wettability was evaluated using “floating” water contact angle method. ► Surface oxidation and texture changes induced by air plasma attributed to the improvement of surface wettability. - Abstract: This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

Surfaces and Air Bacteriology of Selected Wards at a Referral Hospital, Northwest Ethiopia: A Cross-Sectional Study.

Science.gov (United States)

Getachew, Hailu; Derbie, Awoke; Mekonnen, Daniel

2018-01-01

The hospital environment is a source of medically important pathogens that are mostly multidrug resistant (MDR) and posing a major therapeutic challenge. The aim of this study was to assess the surface and air bacteriology of selected wards at Felege Hiwot Referral Hospital (FHRH), Northwest Ethiopia. A cross-sectional study was carried out from 15th February to 30th April 2017. A total of 356 surface and air samples were collected from selected wards using 5% sheep blood agar (Oxoid, UK) and processed at FHRH microbiology laboratory following the standard bacteriological procedures. Pure isolates were tested against the recommended antibiotics using Kirby-Bauer disc diffusion methods, and the susceptibility profile was determined based on Clinical Laboratory Standards Institute (CLSI). Data were entered and analyzed using SPSS version 23 for Windows. Of the total 356 samples processed, 274 were from surfaces and 82 were from air. Among these, 141 (39.6%) showed bacterial growth, yielding a total of 190 isolates. Gram-positive isolates were predominant at 81.6% ( n =155), while the gram negatives were at 18.4% ( n =35). The main isolates were coagulase negative staphylococci ( CoNs ), 44%, followed by S. aureus , 37.4%, and Klebsiella species at 11.6%. The bacterial load on surfaces and air was found beyond the standard limits. Besides, the antimicrobial susceptibility profile of the isolates showed that about 75% of the identified isolates were found resistant for two and more antimicrobial agents tested. This study showed high degree of bacterial load that is beyond the standard limits on both surfaces and air samples of the hospital. Furthermore, some 75% of the isolates were found multidrug resistant. Therefore, it is important to evaluate and strengthen the infection prevention practice of the hospital. Moreover, stakeholders should also reinforce actions to decrease the pressure of antimicrobial resistance in the studied area.

Appendix to Health and Safety Laboratory environmental quarterly, March 1, 1976--June 1, 1976. [Tabulated data on content of lead in surface air and /sup 7/Be, /sup 95/Zr, /sup 137/Cs, /sup 144/Ce, and /sup 90/Sr in surface air, milk, drinking water, and foods sampled in USA

Energy Technology Data Exchange (ETDEWEB)

Hardy, E.P. Jr.

1976-07-01

Tabulated data are presented on: the monthly deposition of /sup 89/Sr and /sup 90/Sr at some 100 world land sites; the content of lead and /sup 7/Be, /sup 95/Zr, /sup 137/Cs, and /sup 144/Ce in samples of surface air from various world sites; and the content of /sup 90/Sr in samples of milk, drinking water, and animal and human diets collected at various locations throughout the USA. (CH)

Improvement of Polytetrafluoroethylene Surface Energy by Repetitive Pulse Non-Thermal Plasma Treatment in Atmospheric Air

International Nuclear Information System (INIS)

Yang Guoqing; Zhang Guanjun; Zhang Wenyuan

2011-01-01

Improvement of polytetrafluoroethylene surface energy by non-thermal plasma treatment is presented, using a nanosecond-positive-edge repetitive pulsed dielectric barrier discharge generator in atmospheric air. The electrical parameters including discharging power, peak and density of micro-discharge current were calculated, and the electron energy was estimated. Surface treatment experiments of polytetrafluoroethylene films were conducted for both different applied voltages and different treating durations. Results show that the surface energy of polytetrafluoroethylene film could be improved to 40 mJ/m 2 or more by plasma treatment. Surface roughness measurement and surface X-ray photoelectron spectroscopy analysis indicate that there are chemical etching and implantation of polar oxygen groups in the sample surface treating process, resulting in the improvement of the sample surface energy. Compared with an AC source of 50 Hz, the dielectric barrier discharges generated by a repetitive pulsed source could provide higher peak power, lower mean power, larger micro-discharge current density and higher electron energy. Therefore, with the same applied peak voltage and treating duration, the improvement of polytetrafluoroethylene surface energy using repetitive pulsed plasma is more effective, and the plasma treatment process based on repetitive pulsed dielectric barrier discharges in air is thus feasible and applicable.

A simple air sampling technique for monitoring nitrous oxide pollution

Energy Technology Data Exchange (ETDEWEB)

Austin, J C; Shaw, R; Moyes, D; Cleaton-Jones, P E

1981-01-01

A simple, inexpensive device for the continuous low-flow sampling of air was devised to permit monitoring of pollution by gaseous anaesthetics. The device consisted of a water-filled Perspex cylinder in which a double-walled flexible-film gas sample collection bag was suspended. Air samples could be aspirated into the collection bag at flow rates of as low as 1 ml min-1 by allowing the water to drain from the cylinder at a controlled rate. The maintenance of sample integrity with aspiration and storage of samples of nitrous oxide in air at concentrations of 1000, 100 and 30 p.p.m. v/v was examined using gas chromatography. The sample bags retained a mean 94% of the nitrous oxide in air samples containing nitrous oxide 25 p.p.m. over a 72-h storage period.

Operational air sampling report, July 1--December 31, 1992

International Nuclear Information System (INIS)

Lyons, C.L.

1993-04-01

Nevada Test Site postshot and tunnel events generate beta/gamma fission products. The REECo air sampling program is designed for measurement of these radionuclides at various facilities supporting these events. Monthly radon sampling is done for documentation of working levels in the tunnel complexes, which would be expected to have the highest radon levels for on-site facilities. Out of a total of 628 air samples taken in the tunnel complexes, 24 showed airborne fission products with concentrations well below their respective Derived Air Concentrations (DAC). All of these were related to event reentry or mineback operations. Tritiated water vapor concentrations were very similar to previously reported levels. The 838 air samples taken at the Area-6 decontamination bays and laundry were again well below any DAC calculation standard and negative for any airborne fission products from laboratory analyses

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunming, E-mail: zcm1229@126.com [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Sunvim Grp Co Ltd, Gaomi 261500 (China); Zhao, Meihua; Wang, Libing; Qu, Lijun [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Men, Yajing [Sunvim Grp Co Ltd, Gaomi 261500 (China)

2017-04-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

International Nuclear Information System (INIS)

Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

2017-01-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Cast Stone Oxidation Front Evaluation: Preliminary Results For Samples Exposed To Moist Air

International Nuclear Information System (INIS)

Langton, C. A.; Almond, P. M.

2013-01-01

The rate of oxidation is important to the long-term performance of reducing salt waste forms because the solubility of some contaminants, e.g., technetium, is a function of oxidation state. TcO 4 - in the salt solution is reduced to Tc(IV) and has been shown to react with ingredients in the waste form to precipitate low solubility sulfide and/or oxide phases. Upon exposure to oxygen, the compounds containing Tc(IV) oxidize to the pertechnetate ion, Tc(VII)O 4 - , which is very soluble. Consequently the rate of technetium oxidation front advancement into a monolith and the technetium leaching profile as a function of depth from an exposed surface are important to waste form performance and ground water concentration predictions. An approach for measuring contaminant oxidation rate (effective contaminant specific oxidation rate) based on leaching of select contaminants of concern is described in this report. In addition, the relationship between reduction capacity and contaminant oxidation is addressed. Chromate (Cr(VI) was used as a non-radioactive surrogate for pertechnetate, Tc(VII), in Cast Stone samples prepared with 5 M Simulant. Cast Stone spiked with pertechnetate was also prepared and tested. Depth discrete subsamples spiked with Cr were cut from Cast Stone exposed to Savannah River Site (SRS) outdoor ambient temperature fluctuations and moist air. Depth discrete subsamples spiked with Tc-99 were cut from Cast Stone exposed to laboratory ambient temperature fluctuations and moist air. Similar conditions are expected to be encountered in the Cast Stone curing container. The leachability of Cr and Tc-99 and the reduction capacities, measured by the Angus-Glasser method, were determined for each subsample as a function of depth from the exposed surface. The results obtained to date were focused on continued method development and are preliminary and apply to the sample composition and curing / exposure conditions described in this report. The Cr oxidation front

Laser ablation of liquid surface in air induced by laser irradiation through liquid medium

Science.gov (United States)

Utsunomiya, Yuji; Kajiwara, Takashi; Nishiyama, Takashi; Nagayama, Kunihito; Kubota, Shiro; Nakahara, Motonao

2010-10-01

The pulse laser ablation of a liquid surface in air when induced by laser irradiation through a liquid medium has been experimentally investigated. A supersonic liquid jet is observed at the liquid-air interface. The liquid surface layer is driven by a plasma plume that is produced by laser ablation at the layer, resulting in a liquid jet. This phenomenon occurs only when an Nd:YAG laser pulse (wavelength: 1064 nm) is focused from the liquid onto air at a low fluence of 20 J/cm2. In this case, as Fresnel’s law shows, the incident and reflected electric fields near the liquid surface layer are superposed constructively. In contrast, when the incident laser is focused from air onto the liquid, a liquid jet is produced only at an extremely high fluence, several times larger than that in the former case. The similarities and differences in the liquid jets and atomization processes are studied for several liquid samples, including water, ethanol, and vacuum oil. The laser ablation of the liquid surface is found to depend on the incident laser energy and laser fluence. A pulse laser light source and high-resolution film are required to observe the detailed structure of a liquid jet.

Ball assisted device for analytical surface sampling

Science.gov (United States)

ElNaggar, Mariam S; Van Berkel, Gary J; Covey, Thomas R

2015-11-03

A system for sampling a surface includes a sampling probe having a housing and a socket, and a rolling sampling sphere within the socket. The housing has a sampling fluid supply conduit and a sampling fluid exhaust conduit. The sampling fluid supply conduit supplies sampling fluid to the sampling sphere. The sampling fluid exhaust conduit has an inlet opening for receiving sampling fluid carried from the surface by the sampling sphere. A surface sampling probe and a method for sampling a surface are also disclosed.

Automated bar coding of air samples at Hanford (ABCASH)

International Nuclear Information System (INIS)

Troyer, G.L.; Brayton, D.D.; McNeece, S.G.

1992-10-01

This article describes the basis, main features and benefits of an automated system for tracking and reporting radioactive air particulate samples. The system was developed due to recognized need for improving the quality and integrity of air sample data related to personnel and environmental protection. The data capture, storage, and retrieval of air sample data are described. The automation aspect of the associated and data input eliminates a large potential for human error. The system utilizes personal computers, handheld computers, a commercial personal computer database package, commercial programming languages, and complete documentation to satisfy the system's automation objective

The EUSTACE project: delivering global, daily information on surface air temperature

Science.gov (United States)

Ghent, D.; Rayner, N. A.

2017-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-2018, https://www.eustaceproject.eu) we have developed an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. This includes developing new "Big Data" analysis methods as the data volumes involved are considerable. We will present recent progress along this road in the EUSTACE project, i.e.: • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

Concentration of the 241Pu in air samples from Chernobyl at Belgrade site estimated by a 241Am in growth method

International Nuclear Information System (INIS)

Vukanac, I.; Novkovic, D.; Djurasevic, M.; Obradovic, Z.; Kandi, A.

2006-01-01

The surface air samples collected in the first half of May 1986 at Vinca- Belgrade site were prepared and measured at the end of the 1991 and beginning of the 1992. year. Activity concentrations of the 137 Cs immediately after the Chernobyl accident were determined by means of gamma spectrometry, while the air activity concentration of 238 Pu and 239,240 Pu were determined by alpha spectrometry, after the plutonium radiochemical separation. The 236 Pu was used as a tracer. The same samples were remeasured after 13 years, during the 2004. The surface air activity concentrations of 241 Pu were estimated by a 241 Am in-growth method. The built up activities of 236 Pu progenies were determined from the recorded spectra and also calculated using the Bateman equations. The 241 Am activity in the remeasured samples, obtained by complex spectral analysis was confirmed by gamma spectrometry. The 241 Pu activity concentration in measured air samples ranged from 240 μBq/m3 to 7800 μBq/m3. The average activity concentration ratio 241 Pu/ 239,240 Pu originated from Chernobyl accident was approximately 100. (authors)

Uncertainties in monitoring of SVOCs in air caused by within-sampler degradation during active and passive air sampling

Science.gov (United States)

Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Přibylová, Petra; Vojta, Šimon; Kohoutek, Jiří; Lammel, Gerhard; Klánová, Jana

2017-10-01

Degradation of semivolatile organic compounds (SVOCs) occurs naturally in ambient air due to reactions with reactive trace gases (e.g., ozone, NOx). During air sampling there is also the possibility for degradation of SVOCs within the air sampler, leading to underestimates of ambient air concentrations. We investigated the possibility of this sampling artifact in commonly used active and passive air samplers for seven classes of SVOCs, including persistent organic pollutants (POPs) typically covered by air monitoring programs, as well as SVOCs of emerging concern. Two active air samplers were used, one equipped with an ozone denuder and one without, to compare relative differences in mass of collected compounds. Two sets of passive samplers were also deployed to determine the influence of degradation during longer deployment times in passive sampling. In active air samplers, comparison of the two sampling configurations suggested degradation of particle-bound polycyclic aromatic hydrocarbons (PAHs), with concentrations up to 2× higher in the denuder-equipped sampler, while halogenated POPs did not have clear evidence of degradation. In contrast, more polar, reactive compounds (e.g., organophosphate esters and current use pesticides) had evidence of losses in the sampler with denuder. This may be caused by the denuder itself, suggesting sampling bias for these compounds can be created when typical air sampling apparatuses are adapted to limit degradation. Passive air samplers recorded up to 4× higher concentrations when deployed for shorter consecutive sampling periods, suggesting that within-sampler degradation may also be relevant in passive air monitoring programs.

Ambient krypton-85 air sampling at Hanford

International Nuclear Information System (INIS)

Trevathan, M.S.; Price, K.R.

1985-01-01

In the fall of 1982, the Environmental Evaluations Section of Pacific Northwest Laboratory (PNL) initiated a network of continuous 85 Kr air samplers located on and around the Hanford Site. This effort was in response to the resumption of operations at a nuclear fuel reprocessing plant located onsite where 85 Kr was to be released during fuel dissolution. Preoperational data were collected using noble gas samplers designed by the Environmental Protection Agency-Las Vegas (EPA-LV). The samplers functioned erratically resulting in excessive maintenance costs and prompted a search for a new sampling system. State-of-the-art 85 Dr sampling methods were reviewed and found to be too costly, too complex and inappropriate for field application, so a simple bag collection system was designed and field tested. The system is composed of a reinforced, heavy plastic bag, connected to a variable flow pump and housed in a weatherproof enclosure. At the end of the four week sampling period the air in the bag is transferred by a compressor into a pressure tank for easy transport to the laboratory for analysis. After several months of operation, the air sampling system has proven its reliability and sensitivity to ambient levels of 85 Kr

Ambient krypton-85 air sampling at Hanford

International Nuclear Information System (INIS)

Trevathan, M.S.; Price, K.R.

1984-10-01

In the fall of 1982, the Environmental Evaluations Section of Pacific Northwest Laboratory (PNL) initiated a network of continuous krypton-85 air samplers located on and around the Hanford Site. This effort was in response to the resumption of operations at a nuclear fuel reprocessing plant located onsite where krypton-85 was to be released during fuel dissolution. Preoperational data were collected using noble gas samplers designed by the Environmental Protection Agency-Las Vegas (EPA-LV). The samplers functioned erratically resulting in excessive maintenance costs and prompted a search for a new sampling system. State of the art krypton-85 sampling methods were reviewed and found to be too costly, too complex and inappropriate for field application, so a simple bag collection system was designed and field tested. The system is composed of a reinforced, heavy plastic bag, connected to a variable flow pump and housed in a weatherproof enclosure. At the end of the four week sampling period the air in the bag is transferred by a compressor into a pressure tank for easy transport to the laboratory for analysis. After several months of operation, the air sampling system has proven its reliability and sensitivity to ambient levels of krypton-85. 3 references, 3 figures, 1 table

30 CFR 90.205 - Approved sampling devices; operation; air flowrate.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved sampling devices; operation; air... LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-COAL MINERS WHO HAVE EVIDENCE OF THE DEVELOPMENT OF PNEUMOCONIOSIS Sampling Procedures § 90.205 Approved sampling devices; operation; air flowrate...

Workplace air monitoring and sampling practices at DOE facilities

International Nuclear Information System (INIS)

Swinth, K.L.; Kenoyer, J.L.; Selby, J.M.

1987-01-01

The Pacific Northwest Laboratory (PNL) surveyed the current air monitoring and sampling practices at U.S. Department of Energy (DOE) facilities as a part of an air monitoring upgrade task. A comprehensive questionnaire was developed and distributed to DOE contractors through the DOE field offices. Twenty-six facilities returned a completed questionnaire. Questionnaire replies indicate a large diversity in air sampling and monitoring practices among DOE facilities. The differences among the facilities exist in monitoring and sampling instrumentation, procedures, calibration, analytical methods, detection levels, and action levels. Many of these differences could be attributed to different operational needs. 5 references, 2 figures, 2 tables

Air sampling procedures to evaluate microbial contamination: a comparison between active and passive methods in operating theatres.

Science.gov (United States)

Napoli, Christian; Marcotrigiano, Vincenzo; Montagna, Maria Teresa

2012-08-02

Since air can play a central role as a reservoir for microorganisms, in controlled environments such as operating theatres regular microbial monitoring is useful to measure air quality and identify critical situations. The aim of this study is to assess microbial contamination levels in operating theatres using both an active and a passive sampling method and then to assess if there is a correlation between the results of the two different sampling methods. The study was performed in 32 turbulent air flow operating theatres of a University Hospital in Southern Italy. Active sampling was carried out using the Surface Air System and passive sampling with settle plates, in accordance with ISO 14698. The Total Viable Count (TVC) was evaluated at rest (in the morning before the beginning of surgical activity) and in operational (during surgery). The mean TVC at rest was 12.4 CFU/m3 and 722.5 CFU/m2/h for active and passive samplings respectively. The mean in operational TVC was 93.8 CFU/m3 (SD = 52.69; range = 22-256) and 10496.5 CFU/m2/h (SD = 7460.5; range = 1415.5-25479.7) for active and passive samplings respectively. Statistical analysis confirmed that the two methods correlate in a comparable way with the quality of air. It is possible to conclude that both methods can be used for general monitoring of air contamination, such as routine surveillance programs. However, the choice must be made between one or the other to obtain specific information.

Air sampling program at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Hulett, S.H.

1975-01-01

An extensive air sampling program has been developed at the Portsmouth Gaseous Diffusion Plant for monitoring the concentrations of radioactive aerosols present in the atmosphere on plantsite as well as in the environs. The program is designed to minimize exposures of employees and the environment to airborne radioactive particulates. Five different air sampling systems, utilizing either filtration or impaction, are employed for measuring airborne alpha and beta-gamma activity produced from 235 U and 234 Th, respectively. Two of the systems have particle selection capabilities: a personal sampler with a 10-mm nylon cyclone eliminates most particles larger than about 10 microns in diameter; and an Annular Kinetic Impactor collects particulates greater than 0.4 microns in diameter which have a density greater than 12-15 gm/cm 3 . A Hi-Volume Air Sampler and an Eberline Model AIM-3 Scintillation Air Monitor are used in collecting short-term samples for assessing compliance with ''ceiling'' standards or peak concentration limits. A film-sort aperture IBM card system is utilized for continuous 8-hour samples. This sampling program has proven to be both practical and effective for assuring accurate monitoring of the airborne activity associated with plant operations

Analysis of 210Pb and 210Po concentrations in surface air by an α spectrometric method

International Nuclear Information System (INIS)

Winkler, R.; Hoetzl, H.; Chatterjee, B.

1981-01-01

A method is presented for determining the concentrations of airborne 210 Pb and 210 Po. The method employs α spectrometry to measure the count rate of 210 Po present on an electrostatic filter sample at two post-sampling times. The individual air concentrations of 210 Po and 210 Pb can be calculated from equations given. Sensitivity of the procedure is about 0.2 fCi 210 Po per m 3 of air. The method was applied to the study of long-term variations and frequency distributions of 210 Po and 210 Pb concentrations in surface air at a nonpolluted location about 10 km outside of Munich, F.R.G., from 1976 through 1979. During this period the average concentration levels were found to be 14.2 fCi 210 Pb per m 3 of air and 0.77 fCi 210 Po per m 3 of air, respectively. (author)

Sampling and identification of gaseous and particle bounded air pollutants

International Nuclear Information System (INIS)

Kettrup, A.

1993-01-01

Air pollutants are gaseous, components of aerosols or particle bounded. Sampling, sample preparation, identification and quantification of compounds depend from kind and chemical composition of the air pollutants. Quality assurance of analytical data must be guaranted. (orig.) [de

Skating on a Film of Air: Drops Impacting on a Surface

Science.gov (United States)

Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

2012-02-01

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

Direct measurements of sample heating by a laser-induced air plasma in pre-ablation spark dual-pulse laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Register, Janna; Scaffidi, Jonathan; Angel, S Michael

2012-08-01

Direct measurements of temperature changes were made using small thermocouples (TC), placed near a laser-induced air plasma. Temperature changes up to ~500 °C were observed. From the measured temperature changes, estimates were made of the amount of heat absorbed per unit area. This allowed calculations to be made of the surface temperature, as a function of time, of a sample heated by the air plasma that is generated during orthogonal pre-ablation spark dual-pulse (DP) LIBS measurements. In separate experiments, single-pulse (SP) LIBS emission and sample ablation rate measurements were performed on nickel at sample temperatures ranging from room temperature to the maximum surface temperature that was calculated using the TC measurement results (500 °C). A small, but real sample temperature-dependent increase in both SP LIBS emission and the rate of sample ablation was found for nickel samples heated up to 500 °C. Comparison of DP LIBS emission enhancement values for bulk nickel samples at room temperature versus the enhanced SP LIBS emission and sample ablation rates observed as a function of increasing sample temperature suggests that sample heating by the laser-induced air plasma plays only a minor role in DP LIBS emission enhancement.

Air sampling procedures to evaluate microbial contamination: a comparison between active and passive methods in operating theatres

Directory of Open Access Journals (Sweden)

Napoli Christian

2012-08-01

Full Text Available Abstract Background Since air can play a central role as a reservoir for microorganisms, in controlled environments such as operating theatres regular microbial monitoring is useful to measure air quality and identify critical situations. The aim of this study is to assess microbial contamination levels in operating theatres using both an active and a passive sampling method and then to assess if there is a correlation between the results of the two different sampling methods. Methods The study was performed in 32 turbulent air flow operating theatres of a University Hospital in Southern Italy. Active sampling was carried out using the Surface Air System and passive sampling with settle plates, in accordance with ISO 14698. The Total Viable Count (TVC was evaluated at rest (in the morning before the beginning of surgical activity and in operational (during surgery. Results The mean TVC at rest was 12.4 CFU/m3 and 722.5 CFU/m2/h for active and passive samplings respectively. The mean in operational TVC was 93.8 CFU/m3 (SD = 52.69; range = 22-256 and 10496.5 CFU/m2/h (SD = 7460.5; range = 1415.5-25479.7 for active and passive samplings respectively. Statistical analysis confirmed that the two methods correlate in a comparable way with the quality of air. Conclusion It is possible to conclude that both methods can be used for general monitoring of air contamination, such as routine surveillance programs. However, the choice must be made between one or the other to obtain specific information.

Surface treatment of aramid fiber by air dielectric barrier discharge plasma at atmospheric pressure

International Nuclear Information System (INIS)

Jia Caixia; Chen Ping; Liu Wei; Li Bin; Wang Qian

2011-01-01

Aramid fiber samples are treated by air dielectric barrier discharge (DBD) plasma at atmospheric pressure; the plasma treatment time is investigated as the major parameter. The effects of this treatment on the fiber surface physical and chemical properties are studied by using surface characterization techniques. Scanning electron microscopy (SEM) is performed to determine the surface morphology changes, X-ray photoelectron spectroscopy (XPS) is analyzed to reveal the surface chemical composition variations and dynamic contact angle analysis (DCAA) is used to examine the changes of the fiber surface wettability. In addition, the wetting behavior of a kind of thermoplastic resin, poly(phthalazinone ether sulfone ketone) (PPESK), on aramid fiber surface is also observed by SEM photos. The study shows that there seems to be an optimum treatment condition for surface modification of aramid fiber by the air DBD plasma. In this paper, after the 12 s, 27.6 W/cm 3 plasma treatment the aramid fiber surface roughness is significantly improved, some new oxygen-containing groups such as C-O, C=O and O=C-O are generated on the fiber surface and the fiber surface wettability is greatly enhanced, which results in the better wetting behavior of PPESK resin on the plasma-treated aramid fiber.

Sampling density for the quantitative evaluation of air trapping

International Nuclear Information System (INIS)

Goris, Michael L.; Robinson, Terry E.

2009-01-01

Concerns have been expressed recently about the radiation burden on patient populations, especially children, undergoing serial radiological testing. To reduce the dose one can change the CT acquisition settings or decrease the sampling density. In this study we determined the minimum desirable sampling density to ascertain the degree of air trapping in children with cystic fibrosis. Ten children with cystic fibrosis in stable condition underwent a volumetric spiral CT scan. The degree of air trapping was determined by an automated algorithm for all slices in the volume, and then for 1/2, 1/4, to 1/128 of all slices, or a sampling density ranging from 100% to 1% of the total volume. The variation around the true value derived from 100% sampling was determined for all other sampling densities. The precision of the measurement remained stable down to a 10% sampling density, but decreased markedly below 3.4%. For a disease marker with the regional variability of air trapping in cystic fibrosis, regardless of observer variability, a sampling density below 10% and even more so, below 3.4%, apparently decreases the precision of the evaluation. (orig.)

Comprehensive Study of Human External Exposure to Organophosphate Flame Retardants via Air, Dust, and Hand Wipes: The Importance of Sampling and Assessment Strategy.

Science.gov (United States)

Xu, Fuchao; Giovanoulis, Georgios; van Waes, Sofie; Padilla-Sanchez, Juan Antonio; Papadopoulou, Eleni; Magnér, Jorgen; Haug, Line Småstuen; Neels, Hugo; Covaci, Adrian

2016-07-19

We compared the human exposure to organophosphate flame retardants (PFRs) via inhalation, dust ingestion, and dermal absorption using different sampling and assessment strategies. Air (indoor stationary air and personal ambient air), dust (floor dust and surface dust), and hand wipes were sampled from 61 participants and their houses. We found that stationary air contains higher levels of ΣPFRs (median = 163 ng/m(3), IQR = 161 ng/m(3)) than personal air (median = 44 ng/m(3), IQR = 55 ng/m(3)), suggesting that the stationary air sample could generate a larger bias for inhalation exposure assessment. Tris(chloropropyl) phosphate isomers (ΣTCPP) accounted for over 80% of ΣPFRs in both stationary and personal air. PFRs were frequently detected in both surface dust (ΣPFRs median = 33 100 ng/g, IQR = 62 300 ng/g) and floor dust (ΣPFRs median = 20 500 ng/g, IQR = 30 300 ng/g). Tris(2-butoxylethyl) phosphate (TBOEP) accounted for 40% and 60% of ΣPFRs in surface and floor dust, respectively, followed by ΣTCPP (30% and 20%, respectively). TBOEP (median = 46 ng, IQR = 69 ng) and ΣTCPP (median = 37 ng, IQR = 49 ng) were also frequently detected in hand wipe samples. For the first time, a comprehensive assessment of human exposure to PFRs via inhalation, dust ingestion, and dermal absorption was conducted with individual personal data rather than reference factors of the general population. Inhalation seems to be the major exposure pathway for ΣTCPP and tris(2-chloroethyl) phosphate (TCEP), while participants had higher exposure to TBOEP and triphenyl phosphate (TPHP) via dust ingestion. Estimated exposure to ΣPFRs was the highest with stationary air inhalation (median =34 ng·kg bw(-1)·day(-1), IQR = 38 ng·kg bw(-1)·day(-1)), followed by surface dust ingestion (median = 13 ng·kg bw(-1)·day(-1), IQR = 28 ng·kg bw(-1)·day(-1)), floor dust ingestion and personal air inhalation. The median dermal exposure on hand wipes was 0.32 ng·kg bw(-1)·day(-1) (IQR

Devices and Methods for Collection and Concentration of Air and Surface Samples for Improved Detection of Microbes onboard ISS, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Protecting the International Space Station (ISS) crew from microbial contaminants is of great importance. Bacterial and fungal contamination of air, surfaces and...

Remote tritium-in-air sampling in reactor building at NAPS

International Nuclear Information System (INIS)

Mitra, S.R.; Lal Chand

2000-01-01

Tritium-in-air activity is an important parameter in PHW reactors from the point of view of internal exposure and heavy water escape from the system. The sampling technique in vogue in PHWRs, for measurement of tritium-in-air activity, requires collection of on the spot sample from different areas using a portable sampler. This sampler uses the bubbler method of sampling. As the areas of sampling are numerous, this technique is time consuming, laborious and can lead to significant internal exposure in areas where tritium-in-air activity is high. This technique is also error prone due to the heavy workload involved. A new scheme, in which the sampling of all the areas of reactor building is done through a sampling station, has been introduced for the first time in NAPS. This sampling station facilitates collection of samples from all the areas of reactor building, remotely and simultaneously at one place thereby reducing time, labour, exposure and error. This paper gives the details of the sampling system installed at NAPS. (author)

Air bubbles and hemolysis of blood samples during transport by pneumatic tube systems.

Science.gov (United States)

Mullins, Garrett R; Bruns, David E

2017-10-01

Transport of blood samples through pneumatic tube systems (PTSs) generates air bubbles in transported blood samples and, with increasing duration of transport, the appearance of hemolysis. We investigated the role of air-bubble formation in PTS-induced hemolysis. Air was introduced into blood samples for 0, 1, 3 or 5min to form air bubbles. Hemolysis in the blood was assessed by (H)-index, lactate dehydrogenase (LD) and potassium in plasma. In an effort to prevent PTS-induced hemolysis, blood sample tubes were completely filled, to prevent air bubble formation, and compared with partially filled samples after PTS transport. We also compared hemolysis in anticoagulated vs clotted blood subjected to PTS transport. As with transport through PTSs, the duration of air bubble formation in blood by a gentle stream of air predicted the extent of hemolysis as measured by H-index (pair space in a blood sample prevented bubble formation and fully protected the blood from PTS-induced hemolysis (ptransport and was partially protected from hemolysis vs anticoagulated blood as indicated by lower LD (ptransport. Prevention of air bubble formation in blood samples during PTS transport protects samples from hemolysis. Copyright © 2017 Elsevier B.V. All rights reserved.

In-air micro-pixe analysis of tissue samples

International Nuclear Information System (INIS)

Tanaka, A.; Ishii, K.; Komori, Y.

2002-01-01

Micro-PIXE is capable of providing spatial distributions of elements in the micro-meter scale and its application to biology is useful to elucidate the cellular metabolism. Since, in this method, a sample target is usually irradiated with proton or α-particle beams in vacuum, beam heating results in evaporation of volatile elements an shrinking of the sample. In order to avoid these side effects, we previously developed a technique of in-air micro-PIXE analysis for samples of cultured cells. In addition to these, analysis of exposed tissue samples from living subjects is highly desirable in biological and medical research. Here, we describe a technique of in-air micro-PIXE analysis of such tissue samples. The target samples of exposed tissue slices from a Donryu rat, in which a tumor had been transplanted, were analyzed with proton micro-beams of 2.6 MeV. We report that the shape of cells and the distribution of volatile elements in the tissue sample remain uncharged when using a target preparation based on a freeze-drying method. (author)

Concentration of 7Be in surface air at Suva, Fiji

International Nuclear Information System (INIS)

Garimella, S.; Koshy, K.

1998-01-01

A high-volume air sampler and a high-resolution gamma-ray spectrometer have been in use since August 1997 at the University of the South Pacific to measure the activity of 7 Be in surface air at Suva, the capital city of Fiji. Preliminary measurements during August - November 1997 indicate that the average concentration of 7 Be in surface air is approximately 4.0 mBq m -3 . Further measurements are in progress

Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

Directory of Open Access Journals (Sweden)

Matthias J. Mayser

2014-06-01

Full Text Available Some plants and animals feature superhydrophobic surfaces capable of retaining a layer of air when submerged under water. Long-term air retaining surfaces (Salvinia-effect are of high interest for biomimetic applications like drag reduction in ship coatings of up to 30%. Here we present a novel method for measuring air volumes and air loss under water. We recorded the buoyancy force of the air layer on leaf surfaces of four different Salvinia species and on one biomimetic surface using a highly sensitive custom made strain gauge force transducer setup. The volume of air held by a surface was quantified by comparing the buoyancy force of the specimen with and then without an air layer. Air volumes retained by the Salvinia-surfaces ranged between 0.15 and 1 L/m2 depending on differences in surface architecture. We verified the precision of the method by comparing the measured air volumes with theoretical volume calculations and could find a good agreement between both values. In this context we present techniques to calculate air volumes on surfaces with complex microstructures. The introduced method also allows to measure decrease or increase of air layers with high accuracy in real-time to understand dynamic processes.

Apparent Surface Free Energy of Polymer/Paper Composite Material Treated by Air Plasma

Directory of Open Access Journals (Sweden)

Konrad Terpiłowski

2017-01-01

Full Text Available Surface plasma treatment consists in changes of surface properties without changing internal properties. In this paper composite polymer/paper material is used for production of packaging in cosmetic industry. There are problems with bonding this material at the time of packaging production due to its properties. Composite surface was treated by air plasma for 1, 10, 20, and 30 s. The advancing and receding contact angles of water, formamide, and diiodomethane were measured using both treated and untreated samples. Apparent surface free energy was estimated using the hysteresis (CAH and Van Oss, Good, Chaudhury approaches (LWAB. Surface roughness was investigated using optical profilometry and identification of after plasma treatment emerging chemical groups was made by means of the XPS (X-ray photoelectron spectroscopy technique. After plasma treatment the values of contact angles decreased which is particularly evident for polar liquids. Apparent surface free energy increased compared to that of untreated samples. Changes of energy value are due to the electron-donor parameter of energy. This parameter increases as a result of adding polar groups at the time of surface plasma activation. Changes of surface properties are combination of increase of polar chemical functional groups, increase on the surface, and surface roughness increase.

Concentration of 7Be in surface air at Suva, Fiji

International Nuclear Information System (INIS)

Garimella, S.; Koshy, K.

1998-01-01

A high-volume air sampler and a high-resolution gamma-ray spectrometer have been in use since August 1997 at the University of the South Pacific to measure the activity of 7 Be in surface air at Suva, the capital city of Fiji. Preliminary measurements during August-November 1997 indicate that the average concentration of 7 Be in surface air is approximately 4.0 mBq m -3 . Further measurements are in progress. (author). 4 refs., 1 fig

A Improved Seabed Surface Sand Sampling Device

Science.gov (United States)

Luo, X.

2017-12-01

In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

Longitudinal study of the contamination of air and of soil surfaces in the vicinity of pig barns by livestock-associated methicillin-resistant Staphylococcus aureus.

Science.gov (United States)

Schulz, Jochen; Friese, Anika; Klees, Sylvia; Tenhagen, Bernd A; Fetsch, Alexandra; Rösler, Uwe; Hartung, Jörg

2012-08-01

During 1 year, samples were taken on 4 days, one sample in each season, from pigs, the floor, and the air inside pig barns and from the ambient air and soil at different distances outside six commercial livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA)-positive pig barns in the north and east of Germany. LA-MRSA was isolated from animals, floor, and air samples in the barn, showing a range of airborne LA-MRSA between 6 and 3,619 CFU/m(3) (median, 151 CFU/m(3)). Downwind of the barns, LA-MRSA was detected in low concentrations (11 to 14 CFU/m(3)) at distances of 50 and 150 m; all upwind air samples were negative. In contrast, LA-MRSA was found on soil surfaces at distances of 50, 150, and 300 m downwind from all barns, but no statistical differences could be observed between the proportions of positive soil surface samples at the three different distances. Upwind of the barns, positive soil surface samples were found only sporadically. Significantly more positive LA-MRSA samples were found in summer than in the other seasons both in air and soil samples upwind and downwind of the pig barns. spa typing was used to confirm the identity of LA-MRSA types found inside and outside the barns. The results show that there is regular airborne LA-MRSA transmission and deposition, which are strongly influenced by wind direction and season, of up to at least 300 m around positive pig barns. The described boot sampling method seems suitable to characterize the contamination of the vicinity of LA-MRSA-positive pig barns by the airborne route.

High surface area carbon for bifunctional air electrodes applied in zinc-air batteries

Energy Technology Data Exchange (ETDEWEB)

Arai, H [on leave from NTT Laboratories (Japan); Mueller, S; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Bifunctional air electrodes with high surface area carbon substrates showed low reduction overpotential, thus are promising for enhancing the energy efficiency and power capability of zinc-air batteries. The improved performance is attributed to lower overpotential due to diffusion of the reaction intermediate, namely the peroxide ion. (author) 1 fig., 2 refs.

Quantification of air plasma chemistry for surface disinfection

International Nuclear Information System (INIS)

Pavlovich, Matthew J; Clark, Douglas S; Graves, David B

2014-01-01

Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O 3 ) and nitrogen oxides (NO and NO 2 , or NO x ) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NO x mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications. (paper)

Quantification of air plasma chemistry for surface disinfection

Science.gov (United States)

Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

2014-12-01

Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

Low-cost monitoring of campylobacter in poultry houses by air sampling and quantitative PCR

DEFF Research Database (Denmark)

Søndergaard, Mette Sofie Rousing; Josefsen, Mathilde Hasseldam; Löfström, Charlotta

2014-01-01

approximately 10(4) and 10(5) CCE per sample for boot swabs and air, respectively. In conclusion, using air samples combined with quantitative real-time PCR, Campylobacter contamination could be detected earlier than by boot swabs and was found to be a more convenient technique for monitoring and/or to obtain......The present study describes the evaluation of a method for the quantification of Campylobacter by air sampling in poultry houses. Sampling was carried out in conventional chicken houses in Poland, in addition to a preliminary sampling in Denmark. Each measurement consisted of three air samples, two...... standard boot swab fecal samples, and one airborne particle count. Sampling was conducted over an 8-week period in three flocks, assessing the presence and levels of Campylobacter in boot swabs and air samples using quantitative real-time PCR. The detection limit for air sampling was approximately 100...

Land Surface Process and Air Quality Research and Applications at MSFC

Science.gov (United States)

Quattrochi, Dale; Khan, Maudood

2007-01-01

This viewgraph presentation provides an overview of land surface process and air quality research at MSFC including atmospheric modeling and ongoing research whose objective is to undertake a comprehensive spatiotemporal analysis of the effects of accurate land surface characterization on atmospheric modeling results, and public health applications. Land use maps as well as 10 meter air temperature, surface wind, PBL mean difference heights, NOx, ozone, and O3+NO2 plots as well as spatial growth model outputs are included. Emissions and general air quality modeling are also discussed.

Tritiated water vapor in the surface air at Tokyo

International Nuclear Information System (INIS)

Inoue, Hisayuki; Katsuragi, Yukio; Shigehara, Koji

1984-01-01

Tritium concentration in water vapor in the air near the surface and in the precipitation at Tokyo was measured during the period from 9 August to 20 November in 1974. From August to the middle of October, tritium mixing ratios in the surface air had relatively higher values except those in air masses which were associated with a typhoon. The mixing ratios of tritium in the air decreased abruptly at the middle of October, which indicates the decrease of tritium influx from aloft. These data exhibit the salient feature that variations in tritium concentration in TR are linear to the reciprocal of the content of water vapor during each period. Tritium concentrations in vapor and rain water collected simultaneously show nearly equal values. One of the reasons for the good correlation of tritium concentration between falling drops and ambient air is considered to be the result of the rapid isotopic exchange. (author)

Sample design considerations of indoor air exposure surveys

International Nuclear Information System (INIS)

Cox, B.G.; Mage, D.T.; Immerman, F.W.

1988-01-01

Concern about the potential for indoor air pollution has prompted recent surveys of radon and NO 2 concentrations in homes and personal exposure studies of volatile organics, carbon monoxide and pesticides, to name a few. The statistical problems in designing sample surveys that measure the physical environment are diverse and more complicated than those encountered in traditional surveys of human attitudes and attributes. This paper addresses issues encountered when designing indoor air quality (IAQ) studies. General statistical concepts related to target population definition, frame creation, and sample selection for area household surveys and telephone surveys are presented. The implications of different measurement approaches are discussed, and response rate considerations are described

Thickened boundary layer theory for air film drag reduction on a van body surface

Science.gov (United States)

Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

2018-05-01

To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

Advanced computer-controlled automatic alpha-beta air sample counter

International Nuclear Information System (INIS)

Howell, W.P.; Bruinekool, D.J.; Stapleton, E.E.

1983-01-01

An improved computer controlled automatic alpha-beta air sample counter was developed, based upon an earlier automatic air sample counter design. The system consists of an automatic sample changer, an electronic counting system utilizing a large silicon diode detector, a small desk-type microcomputer, a high speed matrix printer, and the necessary data interfaces. The system is operated by commands from the keyboard and programs stored on magnetic tape cassettes. The programs provide for background counting, Chi 2 test, radon subtraction, and sample counting for sample periods of one day to one week. Output data are printed by the matrix printer on standard multifold paper. The data output includes gross beta, gross alpha, and plutonium results. Data are automatically corrected for background, counter efficiency, and in the gross alpha and plutonium channels, for the presence of radon

Radon discrimination for work place air samples

International Nuclear Information System (INIS)

Bratvold, T.

1994-01-01

Gross alpha/beta measurement systems are designed solely to identify an incident particle as either an alpha or a beta and register a count accordingly. The tool of choice for radon identification, via decay daughters, is an instrument capable of identifying the energy of incident alpha particles and storing that information separately from detected alpha emissions of different energy. In simpler terms, the desired instrument is an alpha spectroscopy system. K Basins Radiological Control (KBRC) procured an EG ampersand G ORTEC OCTETE PC alpha spectroscopy system to facilitate radon identification on work place air samples. The alpha spectrometer allows for the identification of any alpha emitting isotope based on characteristic alpha emission energies. With this new capability, KBRC will explicitly know whether or not there exists a true airborne concern. Based on historical air quality data, this new information venue will reduce the use of respirators substantially. Situations where an area remains ''on mask'' due solely to the presence of radon daughters on the grab air filter will finally be eliminated. This document serves to introduce a new method for radon daughter detection at the 183KE Health Physics Analytical Laboratory (HPAL). A new work place air sampling analysis program will be described throughout this paper. There is no new technology being introduced, nor any unproven analytical process. The program defined over the expanse of this document simply explains how K Basins Radiological Control will employ their alpha spectrometer

Automated Sampling and Extraction of Krypton from Small Air Samples for Kr-85 Measurement Using Atom Trap Trace Analysis

International Nuclear Information System (INIS)

Hebel, S.; Hands, J.; Goering, F.; Kirchner, G.; Purtschert, R.

2015-01-01

Atom-Trap-Trace-Analysis (ATTA) provides the capability of measuring the Krypton-85 concentration in microlitre amounts of krypton extracted from air samples of about 1 litre. This sample size is sufficiently small to allow for a range of applications, including on-site spot sampling and continuous sampling over periods of several hours. All samples can be easily handled and transported to an off-site laboratory for ATTA measurement, or stored and analyzed on demand. Bayesian sampling methodologies can be applied by blending samples for bulk measurement and performing in-depth analysis as required. Prerequisite for measurement is the extraction of a pure krypton fraction from the sample. This paper introduces an extraction unit able to isolate the krypton in small ambient air samples with high speed, high efficiency and in a fully automated manner using a combination of cryogenic distillation and gas chromatography. Air samples are collected using an automated smart sampler developed in-house to achieve a constant sampling rate over adjustable time periods ranging from 5 minutes to 3 hours per sample. The smart sampler can be deployed in the field and operate on battery for one week to take up to 60 air samples. This high flexibility of sampling and the fast, robust sample preparation are a valuable tool for research and the application of Kr-85 measurements to novel Safeguards procedures. (author)

Impact of indoor surface material on perceived air quality.

Science.gov (United States)

Senitkova, I

2014-03-01

The material combination impact on perceived indoor air quality for various surface interior materials is presented in this paper. The chemical analysis and sensory assessments identifies health adverse of indoor air pollutants (TVOCs). In this study, emissions and odors from different common indoor surface materials were investigated in glass test chamber under standardized conditions. Chemical measurements (TVOC concentration) and sensory assessments (odor intensity, air acceptability) were done after building materials exposure to standardized conditions. The results of the chemical and sensory assessment of individual materials and their combinations are compared and discussed within the paper. The using possibility of individual material surface sorption ability was investigated. The knowledge of targeted sorption effects can be used in the interior design phase. The results demonstrate the various sorption abilities of various indoor materials as well as the various sorption abilities of the same indoor material in various combinations. Copyright © 2013 Elsevier B.V. All rights reserved.

Polycyclic aromatic hydrocarbons in air samples of meat smokehouses

DEFF Research Database (Denmark)

Hansen, Åse Marie; Olsen, I L; Poulsen, O M

1992-01-01

In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approx......In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors...

Air/surface exchange processes of mercury and their linkage to atmospheric pools

International Nuclear Information System (INIS)

Bahlmann, Enno; Ebinghaus, Ralf

2001-01-01

The atmospheric mercury cycle is strongly linked to the terrestrial, aquatic and biologic cycle of mercury via air/surface exchange processes. In order to quantify mercury fluxes from and to the atmosphere to predict local and regional source contributions the methods for flux measurements as well as the physicochemical factors controlling air/surface exchange processes must be assessed. We will describe methods for the determination of mercury and mercury species in ambient air which are basic for investigation of air/surface exchange processes. Further on we will describe approaches for studying the physicochemical factors controlling this processes by using a new laboratory flux measurement system. (author)

Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment

Science.gov (United States)

Castro, V. A.; Ott, C. M.; Pierson, D. L.

2012-01-01

The determination of risk from infectious disease during spaceflight missions is composed of several factors including both the concentration and characteristics of the microorganisms to which the crew are exposed. Thus, having a good understanding of the microbial ecology aboard spacecraft provides the necessary information to mitigate health risks to the crew. While preventive measures are taken to minimize the presence of pathogens on spacecraft, medically significant organisms have been isolated from both the Mir and International Space Station (ISS). Historically, the method for isolation and identification of microorganisms from spacecraft environmental samples depended upon their growth on culture media. Unfortunately, only a fraction of the organisms may grow on a specific culture medium, potentially omitting those microorganisms whose nutritional and physical requirements for growth are not met. To address this bias in our understanding of the ISS environment, the Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment was designed to investigate and develop monitoring technology to provide better microbial characterization. For the SWAB flight experiment, we hypothesized that environmental analysis using non-culture-based technologies would reveal microorganisms, allergens, and microbial toxins not previously reported in spacecraft, allowing for a more complete health assessment. Key findings during this experiment included: a) Generally, advanced molecular techniques were able to reveal a few organisms not recovered using culture-based methods; however, there is no indication that current monitoring is "missing" any medically significant bacteria or fungi. b) Molecular techniques have tremendous potential for microbial monitoring, however, sample preparation and data analysis present challenges for spaceflight hardware. c) Analytical results indicate that some molecular techniques, such as denaturing gradient gel electrophoresis (DGGE), can

Influence of atmospheric rainfall to γ radiation Kerma rate in surface air

International Nuclear Information System (INIS)

Xu Zhe; Wan Jun; Yu Rongsheng

2009-01-01

Objective: To investigate the influence rule of the atmospheric Rainfall to the γ radiation Kerma rate in surface air in order to revise the result of its measurement during rainfall. Methods: The influence factors of rainfall to the measurement of the γ radiation Kerma rate in air were analyzed and then the differential equation of the correlation factors was established theoretically, and by resolving the equation, the mathematical model Was obtained. The model was discussed through several practical examples. Results: The mathematical model was coincided with the tendency of curve about the measured data on the influence rule of rainfall to the γ radiation Kerma rate in surface air. Conclusion: By using the theoretical formula in this article which is established to explain the relationship between the rainfall and the γ radiation Kerma rate in surface air, the influence of rainfall to the γ radiation Kerma rate in surface air could be correctly revised. (authors)

Passive sampling of polychlorinated biphenyls (PCB) in indoor air

DEFF Research Database (Denmark)

Vorkamp, Katrin; Mayer, Philipp

PCBs were widely used in construction materials in the 1906s and 1970s, a period of high building activity in Denmark. The objective of this study was therefore to use passive sampling techniques to develop a simple and cost-effective screening tool for PCBs in indoor air. The study proceeded...... in three phases combining a literature review, laboratory experiments and measurements in buildings potentially containing PCBs in indoor air. The laboratory experiments showed a strong influence of air velocity on the PCB partitioning between air and the passive sampler. Based on the results of the first...

Methods for Sampling and Measurement of Compressed Air Contaminants

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1976-10-15

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Methods for Sampling and Measurement of Compressed Air Contaminants

International Nuclear Information System (INIS)

Stroem, L.

1976-10-01

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Clean Air Markets - Monitoring Surface Water Chemistry

Science.gov (United States)

Learn about how EPA uses Long Term Monitoring (LTM) and Temporily Integrated Monitoring of Ecosystems (TIME) to track the effect of the Clean Air Act Amendments on acidity of surface waters in the eastern U.S.

Surface adsorption behaviour of milk whey protein and pectin mixtures under conditions of air-water interface saturation.

Science.gov (United States)

Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

2011-07-01

Milk whey proteins (MWP) and pectins (Ps) are biopolymer ingredients commonly used in the manufacture of colloidal food products. Therefore, knowledge of the interfacial characteristics of these biopolymers and their mixtures is very important for the design of food dispersion formulations (foams and/or emulsions). In this paper, we examine the adsorption and surface dilatational behaviour of MWP/Ps systems under conditions in which biopolymers can saturate the air-water interface on their own. Experiments were performed at constant temperature (20 °C), pH 7 and ionic strength 0.05 M. Two MWP samples, β-lactoglobulin (β-LG) and whey protein concentrate (WPC), and two Ps samples, low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP) were evaluated. The contribution of biopolymers (MWP and Ps) to the interfacial properties of mixed systems was evaluated on the basis of their individual surface molecular characteristics. Biopolymer bulk concentration capable of saturating the air-water interface was estimated from surface pressure isotherms. Under conditions of interfacial saturation, dynamic adsorption behaviour (surface pressure and dilatational rheological characteristics) of MWP/Ps systems was discussed from a kinetic point of view, in terms of molecular diffusion, penetration and configurational rearrangement at the air-water interface. The main adsorption mechanism in MWP/LMP mixtures might be the MWP interfacial segregation due to the thermodynamic incompatibility between MWP and LMP (synergistic mechanism); while the interfacial adsorption in MWP/HMP mixtures could be characterized by a competitive mechanism between MWP and HMP at the air-water interface (antagonistic mechanism). The magnitude of these phenomena could be closely related to differences in molecular composition and/or aggregation state of MWP (β-LG and WPC). Copyright © 2011 Elsevier B.V. All rights reserved.

Characterization of Viral Load, Viability and Persistence of Influenza A Virus in Air and on Surfaces of Swine Production Facilities.

Directory of Open Access Journals (Sweden)

Victor Neira

Full Text Available Indirect transmission of influenza A virus (IAV in swine is poorly understood and information is lacking on levels of environmental exposure encountered by swine and people during outbreaks of IAV in swine barns. We characterized viral load, viability and persistence of IAV in air and on surfaces during outbreaks in swine barns. IAV was detected in pigs, air and surfaces from five confirmed outbreaks with 48% (47/98 of oral fluid, 38% (32/84 of pen railing and 43% (35/82 of indoor air samples testing positive by IAV RT-PCR. IAV was isolated from air and oral fluids yielding a mixture of subtypes (H1N1, H1N2 and H3N2. Detection of IAV RNA from air was sustained during the outbreaks with maximum levels estimated between 7 and 11 days from reported onset. Our results indicate that during outbreaks of IAV in swine, aerosols and surfaces in barns contain significant levels of IAV potentially representing an exposure hazard to both swine and people.

Wipe sampling for nicotine as a marker of thirdhand tobacco smoke contamination on surfaces in homes, cars, and hotels.

Science.gov (United States)

Quintana, Penelope J E; Matt, Georg E; Chatfield, Dale; Zakarian, Joy M; Fortmann, Addie L; Hoh, Eunha

2013-09-01

Secondhand smoke contains a mixture of pollutants that can persist in air, dust, and on surfaces for months or longer. This persistent residue is known as thirdhand smoke (THS). Here, we detail a simple method of wipe sampling for nicotine as a marker of accumulated THS on surfaces. We analyzed findings from 5 real-world studies to investigate the performance of wipe sampling for nicotine on surfaces in homes, cars, and hotels in relation to smoking behavior and smoking restrictions. The intraclass correlation coefficient for side-by-side samples was 0.91 (95% CI: 0.87-0.94). Wipe sampling for nicotine reliably distinguished between private homes, private cars, rental cars, and hotels with and without smoking bans and was significantly positively correlated with other measures of tobacco smoke contamination such as air and dust nicotine. The sensitivity and specificity of possible threshold values (0.1, 1, and 10 μg/m(2)) were evaluated for distinguishing between nonsmoking and smoking environments. Sensitivity was highest at a threshold of 0.1 μg/m(2), with 74%-100% of smoker environments showing nicotine levels above threshold. Specificity was highest at a threshold of 10 μg/m(2), with 81%-100% of nonsmoker environments showing nicotine levels below threshold. The optimal threshold will depend on the desired balance of sensitivity and specificity and on the types of smoking and nonsmoking environments. Surface wipe sampling for nicotine is a reliable, valid, and relatively simple collection method to quantify THS contamination on surfaces across a wide range of field settings and to distinguish between nonsmoking and smoking environments.

ENVIRONMENTAL SAMPLING USING LOCATION SPECIFIC AIR MONITORING IN BULK HANDLING FACILITIES

Energy Technology Data Exchange (ETDEWEB)

Sexton, L.; Hanks, D.; Degange, J.; Brant, H.; Hall, G.; Cable-Dunlap, P.; Anderson, B.

2011-06-07

Since the introduction of safeguards strengthening measures approved by the International Atomic Energy Agency (IAEA) Board of Governors (1992-1997), international nuclear safeguards inspectors have been able to utilize environmental sampling (ES) (e.g. deposited particulates, air, water, vegetation, sediments, soil and biota) in their safeguarding approaches at bulk uranium/plutonium handling facilities. Enhancements of environmental sampling techniques used by the IAEA in drawing conclusions concerning the absence of undeclared nuclear materials or activities will soon be able to take advantage of a recent step change improvement in the gathering and analysis of air samples at these facilities. Location specific air monitoring feasibility tests have been performed with excellent results in determining attribute and isotopic composition of chemical elements present in an actual test-bed sample. Isotopic analysis of collected particles from an Aerosol Contaminant Extractor (ACE) collection, was performed with the standard bulk sampling protocol used throughout the IAEA network of analytical laboratories (NWAL). The results yielded bulk isotopic values expected for the operations. Advanced designs of air monitoring instruments such as the ACE may be used in gas centrifuge enrichment plants (GCEP) to detect the production of highly enriched uranium (HEU) or enrichments not declared by a State. Researchers at Savannah River National Laboratory in collaboration with Oak Ridge National Laboratory are developing the next generation of ES equipment for air grab and constant samples that could become an important addition to the international nuclear safeguards inspector's toolkit. Location specific air monitoring to be used to establish a baseline environmental signature of a particular facility employed for comparison of consistencies in declared operations will be described in this paper. Implementation of air monitoring will be contrasted against the use of smear

Development of activated charcoal impregnated air sampling filter media : their characteristics and use

International Nuclear Information System (INIS)

Khan, A.A.; Ramarathinam, K.; Gupta, S.K.; Deshingkar, D.S.; Kishore, A.G.

1975-01-01

Because of its low maximum permissible concentration in air, air-borne radioiodine must be accurately monitored in contaminated air streams, in the working environment and handling facilities, before release to the environment from the nuclear facilities. Activated charcoal impregnated air sampling filter media are found to be most suitable for monitoring airborne iodine-131. Because of its simplicity and reproducible nature in assessment of air-borne radioactive iodine, the work on the development of such media was undertaken in order to find a suitable substitute for imported activated charcoal impregnated air sampling filter media. Eight different media of such type were developed, evaluated and compared with two imported media. Best suitable medium is recommended for its use in air-borne iodine sampling which was found to be even better suited than imported media of such type. (author)

Technical basis and evaluation criteria for an air sampling/monitoring program

International Nuclear Information System (INIS)

Gregory, D.C.; Bryan, W.L.; Falter, K.G.

1993-01-01

Air sampling and monitoring programs at DOE facilities need to be reviewed in light of revised requirements and guidance found in, for example, DOE Order 5480.6 (RadCon Manual). Accordingly, the Oak Ridge National Laboratory (ORNL) air monitoring program is being revised and placed on a sound technical basis. A draft technical basis document has been written to establish placement criteria for instruments and to guide the ''retrospective sampling or real-time monitoring'' decision. Facility evaluations are being used to document air sampling/monitoring needs, and instruments are being evaluated in light of these needs. The steps used to develop this program and the technical basis for instrument placement are described

Effect of air gap on uniformity of large-scale surface-wave plasma

International Nuclear Information System (INIS)

Lan Chaohui; Hu Xiwei; Jiang Zhonghe; Liu Minghai

2009-01-01

The effect of air gap on the uniformity of large-scale surface-wave plasma (SWP) in a rectangular chamber device is studied by using three-dimensional numerical analyses based on the finite difference time-domain (FDTD) approximation to Maxwell's equations and plasma fluid model. The spatial distributions of surface wave excited by slot-antenna array and the plasma parameters such as electron density and temperature are presented. For different air gap thicknesses, the results show that the existence of air gap would severely weaken the excitations of the surface wave and thereby the SWP. Thus the air gap should be eliminated completely in the design of the SWP source, which is opposite to the former research results. (authors)

Estimating Sampling Biases and Measurement Uncertainties of AIRS-AMSU-A Temperature and Water Vapor Observations Using MERRA Reanalysis

Science.gov (United States)

Hearty, Thomas J.; Savtchenko, Andrey K.; Tian, Baijun; Fetzer, Eric; Yung, Yuk L.; Theobald, Michael; Vollmer, Bruce; Fishbein, Evan; Won, Young-In

2014-01-01

We use MERRA (Modern Era Retrospective-Analysis for Research Applications) temperature and water vapor data to estimate the sampling biases of climatologies derived from the AIRS/AMSU-A (Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A) suite of instruments. We separate the total sampling bias into temporal and instrumental components. The temporal component is caused by the AIRS/AMSU-A orbit and swath that are not able to sample all of time and space. The instrumental component is caused by scenes that prevent successful retrievals. The temporal sampling biases are generally smaller than the instrumental sampling biases except in regions with large diurnal variations, such as the boundary layer, where the temporal sampling biases of temperature can be +/- 2 K and water vapor can be 10% wet. The instrumental sampling biases are the main contributor to the total sampling biases and are mainly caused by clouds. They are up to 2 K cold and greater than 30% dry over mid-latitude storm tracks and tropical deep convective cloudy regions and up to 20% wet over stratus regions. However, other factors such as surface emissivity and temperature can also influence the instrumental sampling bias over deserts where the biases can be up to 1 K cold and 10% wet. Some instrumental sampling biases can vary seasonally and/or diurnally. We also estimate the combined measurement uncertainties of temperature and water vapor from AIRS/AMSU-A and MERRA by comparing similarly sampled climatologies from both data sets. The measurement differences are often larger than the sampling biases and have longitudinal variations.

Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air plasma treatment.

Science.gov (United States)

Banerjee, K K; Kumar, S; Bremmell, K E; Griesser, H J

2010-11-01

Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Known volume air sampling pump. Final summary report Jun 1975--Nov 1976

International Nuclear Information System (INIS)

McCullough, J.E.; Peterson, A.

1976-11-01

The purpose of this development program was to design and develop a known volume air sampling pump for use in measuring the amount of radioactive material in the atmosphere of an underground uranium mine. The principal nuclear radiation hazard to underground uranium mines comes from the mine atmosphere. Daughter products of radon-222 are inhaled by the miner resulting in a relatively high lung cancer rate among these workers. Current exposure control practice employs spot sampling in working areas to measure working level values. Currently available personal air sampling pumps fail to deliver known volumes of air under widely changing differential pressures. A unique type of gas pump known as the scroll compressor, developed by Arthur D. Little, Inc., that has no values and few moving parts is expected to provide a practical, efficient, and dependable air pump for use in dosimeters. The three deliverable known volume air sampling pumps resulting from this work incorporate a scroll pump, drive motor, speed control electronics, and battery pack in a container suitable for attachment to a miner's belt

32 CFR 806.27 - Samples of Air Force FOIA processing documents.

Science.gov (United States)

2010-07-01

... ADMINISTRATION AIR FORCE FREEDOM OF INFORMATION ACT PROGRAM § 806.27 Samples of Air Force FOIA processing... determination within 20 workdays, we have instituted multitrack processing of requests. Based on the information... source; responsive records were part of the Air Force's decision-making process, and the prerelease...

A prospective survey of air and surface fungal contamination in a medical mycology laboratory at a tertiary care university hospital.

Science.gov (United States)

Sautour, Marc; Dalle, Frédéric; Olivieri, Claire; L'ollivier, Coralie; Enderlin, Emilie; Salome, Elsa; Chovelon, Isabelle; Vagner, Odile; Sixt, Nathalie; Fricker-Pap, Véronique; Aho, Serge; Fontaneau, Olivier; Cachia, Claire; Bonnin, Alain

2009-04-01

Invasive filamentous fungi infections resulting from inhalation of mold conidia pose a major threat in immunocompromised patients. The diagnosis is based on direct smears, cultural symptoms, and culturing fungi. Airborne conidia present in the laboratory environment may cause contamination of cultures, resulting in false-positive diagnosis. Baseline values of fungal contamination in a clinical mycology laboratory have not been determined to date. A 1-year prospective survey of air and surface contamination was conducted in a clinical mycology laboratory during a period when large construction projects were being conducted in the hospital. Air was sampled with a portable air system impactor, and surfaces were sampled with contact Sabouraud agar plates. The collected data allowed the elaboration of Shewhart graphic charts. Mean fungal loads ranged from 2.27 to 4.36 colony forming units (cfu)/m(3) in air and from 0.61 to 1.69 cfu/plate on surfaces. Strict control procedures may limit the level of fungal contamination in a clinical mycology laboratory even in the context of large construction projects at the hospital site. Our data and the resulting Shewhart graphic charts provide baseline values to use when monitoring for inappropriate variations of the fungal contamination in a mycology laboratory as part of a quality assurance program. This is critical to the appropriate management of the fungal risk in hematology, cancer and transplantation patients.

Biphilic Surfaces for Enhanced Water Collection from Humid Air

Science.gov (United States)

Benkoski, Jason; Gerasopoulos, Konstantinos; Luedeman, William

Surface wettability plays an important role in water recovery, distillation, dehumidification, and heat transfer. The efficiency of each process depends on the rate of droplet nucleation, droplet growth, and mass transfer. Unfortunately, hydrophilic surfaces are good at nucleation but poor at shedding. Hydrophobic surfaces are the reverse. Many plants and animals overcome this tradeoff through biphilic surfaces with patterned wettability. For example, the Stenocara beetle uses hydrophilic patches on a superhydrophobic background to collect fog from air. Cribellate spiders similarly collect fog on their webs through periodic spindle-knot structures. In this study, we investigate the effects of wettability patterns on the rate of water collection from humid air. The steady state rate of water collection per unit area is measured as a function of undercooling, angle of inclination, water contact angle, hydrophilic patch size, patch spacing, area fraction, and patch height relative to the hydrophobic background. We then model each pattern by comparing the potential and kinetic energy of a droplet as it rolls downwards at a fixed angle. The results indicate that the design rules for collecting fog differ from those for condensation from humid air. The authors gratefully acknowledge the Office of Naval Research for financial support through Grant Number N00014-15-1-2107.

Symmetric scaling properties in global surface air temperature anomalies

Science.gov (United States)

Varotsos, Costas A.; Efstathiou, Maria N.

2015-08-01

We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

Measuring PM2.5, Ultrafine Particles, Nicotine Air and Wipe Samples Following the Use of Electronic Cigarettes.

Science.gov (United States)

Melstrom, Paul; Koszowski, Bartosz; Thanner, Meridith Hill; Hoh, Eunha; King, Brian; Bunnell, Rebecca; McAfee, Tim

2017-09-01

Few studies have examined the extent of inhalation or dermal contact among bystanders following short-term, secondhand e-cigarette exposure. Measure PM2.5 (particles e-cigarette exposure. E-cigarettes were used ad libitum by three experienced users for 2 hours during two separate sessions (disposable e-cigarettes, then tank-style e-cigarettes, or "tanks") in a 1858 ft3 room. We recorded: uncorrected PM2.5 (using SidePak); UF (using P-Trak); air nicotine concentrations (using air samplers; SKC XAD-4 canisters); ambient air exchange rate (using an air capture hood). Wipe samples were taken by wiping 100 cm2 room surfaces pre- and post- both sessions, and clean cloth wipes were worn during the exposure and collected at the end. Uncorrected PM2.5 and UF were higher (p e-cigarette use can produce: elevated PM2.5; elevated UF; nicotine in the air; and accumulation of nicotine on surfaces and clothing. Short-term indoor e-cigarette use produced accumulation of nicotine on surfaces and clothing, which could lead to dermal exposure to nicotine. Short-term e-cigarette use produced elevated PM2.5 and ultrafine particles, which could lead to secondhand inhalation of these particles and any chemicals associated with them by bystanders. We measured significant differences in PM2.5 and ultrafine particles between disposable e-cigarettes and tank-style e-cigarettes, suggesting a difference in the exposure profiles of e-cigarette products. Published by Oxford University Press on behalf of Society for Research on Nicotine and Tobacco 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Programmable automatic alpha--beta air sample counter

International Nuclear Information System (INIS)

Howell, W.P.

1978-01-01

A programmable automatic alpha-beta air sample counter was developed for routine sample counting by operational health physics personnel. The system is composed of an automatic sample changer utilizing a large silicon diode detector, an electronic counting system with energy analysis capability, an automatic data acquisition controller, an interface module, and a teletypewriter with paper tape punch and paper tape reader. The system is operated through the teletypewriter keyboard and the paper tape reader, which are used to instruct the automatic data acquisition controller. Paper tape programs are provided for background counting, Chi 2 test, and sample counting. Output data are printed by the teletypewriter on standard continuous roll or multifold paper. Data are automatically corrected for background and counter efficiency

An advanced computer-controlled automatic alpha-beta air sample counter

International Nuclear Information System (INIS)

Howell, W.P.; Bruinekool, D.J.; Stapleton, E.E.

1984-01-01

An improved computer-controlled automatic alpha-beta air sample counter was developed, based upon an earlier automatic air sample counter design. The system consists of an automatic sample changer, an electronic counting system utilizing a large silicon diode detector, a small desk-type microcomputer, a high-speed matrix printer and the necessary data interfaces. The system is operated by commands from the keyboard and programs stored on magnetic tape cassettes. The programs provide for background counting, Chi 2 test, radon subtraction and sample counting for sample periods of one day to one week. Output data are printed by the matrix printer on standard multifold paper. The data output includes gross beta, gross alpha and plutonium results. Data are automatically corrected for background, counter efficiency, and in the gross alpha and plutonium channels, for the presence of radon

Air sampling methods to evaluate microbial contamination in operating theatres: results of a comparative study in an orthopaedics department.

Science.gov (United States)

Napoli, C; Tafuri, S; Montenegro, L; Cassano, M; Notarnicola, A; Lattarulo, S; Montagna, M T; Moretti, B

2012-02-01

To evaluate the level of microbial contamination of air in operating theatres using active [i.e. surface air system (SAS)] and passive [i.e. index of microbial air contamination (IMA) and nitrocellulose membranes positioned near the wound] sampling systems. Sampling was performed between January 2010 and January 2011 in the operating theatre of the orthopaedics department in a university hospital in Southern Italy. During surgery, the mean bacterial loads recorded were 2232.9 colony-forming units (cfu)/m(2)/h with the IMA method, 123.2 cfu/m(3) with the SAS method and 2768.2 cfu/m(2)/h with the nitrocellulose membranes. Correlation was found between the results of the three methods. Staphylococcus aureus was detected in 12 of 60 operations (20%) with the membranes, five (8.3%) operations with the SAS method, and three operations (5%) with the IMA method. Use of nitrocellulose membranes placed near a wound is a valid method for measuring the microbial contamination of air. This method was more sensitive than the IMA method and was not subject to any calibration bias, unlike active air monitoring systems. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

An analytical method for trifluoroacetic Acid in water and air samples using headspace gas chromatographic determination of the methyl ester.

Science.gov (United States)

Zehavi, D; Seiber, J N

1996-10-01

An analytical method has been developed for the determination of trace levels of trifluoroacetic acid (TFA), an atmospheric breakdown product of several of the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon (HCFC) replacements for the chlorofluorocarbon (CFC) refrigerants, in water and air. TFA is derivatized to the volatile methyl trifluoroacetate (MTFA) and determined by automated headspace gas chromatography (HSGC) with electron-capture detection or manual HSGC using GC/MS in the selected ion monitoring (SIM) mode. The method is based on the reaction of an aqueous sample containing TFA with dimethyl sulfate (DMS) in concentrated sulfuric acid in a sealed headspace vial under conditions favoring distribution of MTFA to the vapor phase. Water samples are prepared by evaporative concentration, during which TFA is retained as the anion, followed by extraction with diethyl ether of the acidified sample and then back-extraction of TFA (as the anion) in aqueous bicarbonate solution. The extraction step is required for samples with a relatively high background of other salts and organic materials. Air samples are collected in sodium bicarbonate-glycerin-coated glass denuder tubes and prepared by rinsing the denuder contents with water to form an aqueous sample for derivatization and analysis. Recoveries of TFA from spiked water, with and without evaporative concentration, and from spiked air were quantitative, with estimated detection limits of 10 ng/mL (unconcentrated) and 25 pg/mL (concentrated 250 mL:1 mL) for water and 1 ng/m(3) (72 h at 5 L/min) for air. Several environmental air, fogwater, rainwater, and surface water samples were successfully analyzed; many showed the presence of TFA.

Profiling quinones in ambient air samples collected from the Athabasca region (Canada).

Science.gov (United States)

Wnorowski, Andrzej; Charland, Jean-Pierre

2017-12-01

This paper presents new findings on polycyclic aromatic hydrocarbon oxidation products-quinones that were collected in ambient air samples in the proximity of oil sands exploration. Quinones were characterized for their diurnal concentration variability, phase partitioning, and molecular size distribution. Gas-phase (GP) and particle-phase (PM) ambient air samples were collected separately in the summer; a lower quinone content was observed in the PM samples from continuous 24-h sampling than from combined 12-h sampling (day and night). The daytime/nocturnal samples demonstrated that nighttime conditions led to lower concentrations and some quinones not being detected. The highest quinone levels were associated with wind directions originating from oil sands exploration sites. The statistical correlation with primary pollutants directly emitted from oil sands industrial activities indicated that the bulk of the detected quinones did not originate directly from primary emission sources and that quinone formation paralleled a reduction in primary source NO x levels. This suggests a secondary chemical transformation of primary pollutants as the origin of the determined quinones. Measurements of 19 quinones included five that have not previously been reported in ambient air or in Standard Reference Material 1649a/1649b and seven that have not been previously measured in ambient air in the underivatized form. This is the first paper to report on quinone characterization in secondary organic aerosols originating from oil sands activities, to distinguish chrysenequinone and anthraquinone positional isomers in ambient air, and to report the requirement of daylight conditions for benzo[a]pyrenequinone and naphthacenequinone to be present in ambient air. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Improving the indoor air quality by using a surface emissions trap

Science.gov (United States)

Markowicz, Pawel; Larsson, Lennart

2015-04-01

The surface emissions trap, an adsorption cloth developed for reducing emissions of volatile organic compounds and particulate matter from surfaces while allowing evaporation of moisture, was used to improve the indoor air quality of a school building with elevated air concentrations of 2-ethyl-1-hexanol. An improvement of the perceived air quality was noticed a few days after the device had been attached on the PVC flooring. In parallel, decreased air concentrations of 2-ethyl-1-hexanol were found as well as a linear increase of the amounts of the same compound adsorbed on the installed cloth as observed up to 13 months after installation. Laboratory studies revealed that the performance of the device is not affected by differences in RH (35-85%), temperature (30-40 °C) or by accelerated aging simulating up to 10 years product lifetime, and, from a blinded exposure test, that the device efficiently blocks chemical odors. This study suggests that the device may represent a fast and efficient means of restoring the indoor air quality in a building e.g. after water damage leading to irritating and potentially harmful emissions from building material surfaces indoors.

Identifying anthropogenic anomalies in air, surface and groundwater temperatures in Germany.

Science.gov (United States)

Benz, Susanne A; Bayer, Peter; Blum, Philipp

2017-04-15

Human activity directly influences ambient air, surface and groundwater temperatures. The most prominent phenomenon is the urban heat island effect, which has been investigated particularly in large and densely populated cities. This study explores the anthropogenic impact on the thermal regime not only in selected urban areas, but on a countrywide scale for mean annual temperature datasets in Germany in three different compartments: measured surface air temperature, measured groundwater temperature, and satellite-derived land surface temperature. Taking nighttime lights as an indicator of rural areas, the anthropogenic heat intensity is introduced. It is applicable to each data set and provides the difference between measured local temperature and median rural background temperature. This concept is analogous to the well-established urban heat island intensity, but applicable to each measurement point or pixel of a large, even global, study area. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1km×1km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity, albeit the different compartments are partially influenced through unrelated processes; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities >4K. Overall, surface anthropogenic heat intensities >0K and

Estimation of bare soil surface temperature from air temperature and ...

African Journals Online (AJOL)

Soil surface temperature has critical influence on climate, agricultural and hydrological activities since it serves as a good indicator of the energy budget of the earth's surface. Two empirical models for estimating soil surface temperature from air temperature and soil depth temperature were developed. The coefficient of ...

Solubility testing of actinides on breathing-zone and area air samples

International Nuclear Information System (INIS)

Metzger, R.L.; Jessop, B.H.; McDowell, B.L.

1996-02-01

A solubility testing method for several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS reg-sign) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of U 3 O 8 . Profiles developed for U 3 O 8 samples show good agreement with in vitro and in vivo tests performed by other investigators on samples from the same uranium mills

Analysis of the Touch-And-Go Surface Sampling Concept for Comet Sample Return Missions

Science.gov (United States)

Mandic, Milan; Acikmese, Behcet; Bayard, David S.; Blackmore, Lars

2012-01-01

This paper studies the Touch-and-Go (TAG) concept for enabling a spacecraft to take a sample from the surface of a small primitive body, such as an asteroid or comet. The idea behind the TAG concept is to let the spacecraft descend to the surface, make contact with the surface for several seconds, and then ascend to a safe location. Sampling would be accomplished by an end-effector that is active during the few seconds of surface contact. The TAG event is one of the most critical events in a primitive body sample-return mission. The purpose of this study is to evaluate the dynamic behavior of a representative spacecraft during the TAG event, i.e., immediately prior, during, and after surface contact of the sampler. The study evaluates the sample-collection performance of the proposed sampling end-effector, in this case a brushwheel sampler, while acquiring material from the surface during the contact. A main result of the study is a guidance and control (G&C) validation of the overall TAG concept, in addition to specific contributions to demonstrating the effectiveness of using nonlinear clutch mechanisms in the sampling arm joints, and increasing the length of the sampling arms to improve robustness.

Intelligent sampling for the measurement of structured surfaces

International Nuclear Information System (INIS)

Wang, J; Jiang, X; Blunt, L A; Scott, P J; Leach, R K

2012-01-01

Uniform sampling in metrology has known drawbacks such as coherent spectral aliasing and a lack of efficiency in terms of measuring time and data storage. The requirement for intelligent sampling strategies has been outlined over recent years, particularly where the measurement of structured surfaces is concerned. Most of the present research on intelligent sampling has focused on dimensional metrology using coordinate-measuring machines with little reported on the area of surface metrology. In the research reported here, potential intelligent sampling strategies for surface topography measurement of structured surfaces are investigated by using numerical simulation and experimental verification. The methods include the jittered uniform method, low-discrepancy pattern sampling and several adaptive methods which originate from computer graphics, coordinate metrology and previous research by the authors. By combining the use of advanced reconstruction methods and feature-based characterization techniques, the measurement performance of the sampling methods is studied using case studies. The advantages, stability and feasibility of these techniques for practical measurements are discussed. (paper)

Sampling for Air Chemical Emissions from the Life Sciences Laboratory II

Energy Technology Data Exchange (ETDEWEB)

Ballinger, Marcel Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lindberg, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-03-30

Sampling for air chemical emissions from the Life Science Laboratory II (LSL-II) ventilation stack was performed in an effort to determine potential exposure of maintenance staff to laboratory exhaust on the building roof. The concern about worker exposure was raised in December 2015 and several activities were performed to assist in estimating exposure concentrations. Data quality objectives were developed to determine the need for and scope and parameters of a sampling campaign to measure chemical emissions from research and development activities to the outside air. The activities provided data on temporal variation of air chemical concentrations and a basis for evaluating calculated emissions. Sampling for air chemical emissions was performed in the LSL-II ventilation stack over the 6-week period from July 26 to September 1, 2016. A total of 12 sampling events were carried out using 16 sample media. Resulting analysis provided concentration data on 49 analytes. All results were below occupational exposure limits and most results were below detection limits. When compared to calculated emissions, only 5 of the 49 chemicals had measured concentrations greater than predicted. This sampling effort will inform other study components to develop a more complete picture of a worker’s potential exposure from LSL-II rooftop activities. Mixing studies were conducted to inform spatial variation in concentrations at other rooftop locations and can be used in conjunction with these results to provide temporal variations in concentrations for estimating the potential exposure to workers working in and around the LSL-II stack.

Capacity constrained blue-noise sampling on surfaces

KAUST Repository

Zhang, Sen

2015-11-27

We present a novel method for high-quality blue-noise sampling on mesh surfaces with prescribed cell-sizes for the underlying tessellation (capacity constraint). Unlike the previous surface sampling approach that only uses capacity constraints as a regularizer of the Centroidal Voronoi Tessellation (CVT) energy, our approach enforces an exact capacity constraint using the restricted power tessellation on surfaces. Our approach is a generalization of the previous 2D blue noise sampling technique using an interleaving optimization framework. We further extend this framework to handle multi-capacity constraints. We compare our approach with several state-of-the-art methods and demonstrate that our results are superior to previous work in terms of preserving the capacity constraints.

Using silver nano particles for sampling of toxic mercury vapors from industrial air sample

Directory of Open Access Journals (Sweden)

M. Osanloo

2014-05-01

.Conclusion: The presented adsorbent is very useful for sampling of the trace amounts of mercury vapors from air. Moreover, it can be regenerated easily is suitable or sampling at 25 to 70 °C. Due to oxidation of silver and reduction in uptake of nanoparticles, oven temperature of 245 °C is used for the recovery of metallic silver. Low amount of adsorbent, high absorbency, high repeatability for sampling, low cost and high accuracy are of the advantages of the presented method.

Quantitative analysis of untreated oil samples in in-air PIXE

International Nuclear Information System (INIS)

Sera, K.; Goto, S.; Takahashi, C.; Saitoh, Y.

2010-01-01

The method of quantitative analysis of oil samples in in-air PIXE has been developed on the basis of a standard-free method. The components of the continuous X-rays originated from air and backing film can be exactly subtracted using a blank spectrum after normalization by the yields of Ar K-α X-rays. The method was developed using nine oil samples including standard oils and its accuracy was confirmed by comparing the results with those obtained by the internal-standard method. Validity of the method for practical oil samples was confirmed for various kinds of oils such as engine, machine and cooking oils. It was found that the method is effective for various kinds of oils whatever elements we designate as an index element. (author)

A Novel Method making direct use of AIRS and IASI Calibrated Radiances for Measuring Trends in Surface Temperatures

Science.gov (United States)

Aumann, H. H.; Ruzmaikin, A.

2014-12-01

Making unbiased measurements of trends in the surface temperatures, particularly on a gobal scale, is challenging: While the non-frozen oceans temperature measurements are plentiful and accurate, land and polar areas are much less accurately or fairly sampled. Surface temperature deduced from infrared radiometers on polar orbiting satellites (e.g. the Atmospheric Infrared Sounder (AIRS) at 1:30PM, the Interferometer Atmosphere Sounding Interferometer (IASI) at 9:30 AM and the MODerate resolution Imaging Spectro-radiometer (MODIS) at 1:30PM), can produce what appear to be well sampled data, but dealing with clouds either by cloud filtering (MODIS, IASI) or cloud-clearing (AIRS) can create sampling bias. We use a novel method: Random Nadir Sampling (RNS) combined with Probability Density Function (PDF) analysis. We analyze the trend in the PDF of st1231, the water vapor absorption corrected brightness temperatures measured in the 1231 cm-1 atmospheric window channel. The advantage of this method is that trends can be directly traced to the known, less than 3 mK/yr trend for AIRS, in st1231. For this study we created PDFs from 22,000 daily RNS from the AIRS and IASI data. We characterized the PDFs by its daily 90%tile value, st1231p90, and analysed the statistical properties of the this time series between 2002 and 2014. The method was validated using the daily NOAA SST (RTGSST) from the non-frozen oceans: The mean, seasonal variability and anomaly trend of st1231p90 agree with the corrsponding values from the RTGSST and the anomaly correlation is larger than 0.9. Preliminary results (August 2014) confirm the global hiatus in the increase of the globally averaged surface temperatures between 2002 and 2014, with a change of less than 10 mK/yr. This uncertainty is dominated by the large interannual variability related to El Niño events. Further insite is gained by analyzing land/ocean, day/night, artic and antarctic trends. We observe a massive warming trend in the

Final work plan : indoor air and ambient air sampling near the former CCC/USDA grain storage facility in Everest, Kansas.

Energy Technology Data Exchange (ETDEWEB)

LaFreniere, L. M. (Environmental Science Division)

2010-05-24

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at the western edge of Everest, Kansas, from the early 1950s to the early 1970s. Sampling by the Kansas Department of Health and Environment (KDHE) in 1997 resulted in the detection of carbon tetrachloride in one domestic well (the Nigh well) northwest of the former facility. On behalf of the CCC/USDA, Argonne National Laboratory subsequently conducted a series of investigations to characterize the contamination (Argonne 2003, 2006a,b,c). Automatic, continuous monitoring of groundwater levels began in 2002 and is ongoing at six locations. The results have consistently indicated groundwater flow toward the north-northwest from the former CCC/USDA property to the Nigh property, then west-southwest from the Nigh property to the intermittent creek. Sitewide periodic groundwater and surface water sampling with analysis for volatile organic compounds (VOCs) began in 2008. Argonne's combined data indicate no significant downgradient extension of contamination since 2000. At present, the sampling is annual, as approved by the KDHE (2009) in response to a plan developed for the CCC/USDA (Argonne 2009). This document presents a plan for collecting indoor air samples in homes located along and adjacent to the defined extent of the carbon tetrachloride contamination. The plan was requested by the KDHE. Ambient air samples to represent the conditions along this pathway will also be taken. The purpose of the proposed work is to satisfy KDHE requirements and to collect additional data for assessing the risk to human health due to the potential upward migration of carbon tetrachloride and its primary degradation product (chloroform) into homes located in close proximity to the former grain storage facility, as well as along and within 100 ft laterally from the currently defined plume emanating from the former Everest facility. Investigation of the indoor air

High-throughput liquid-absorption air-sampling apparatus and methods

Science.gov (United States)

Zaromb, Solomon

2000-01-01

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is 20% for vapors or airborne particulates in the 2-3.mu. range and >50% for particles larger than 4.mu.. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

High-throughput liquid-absorption air-sampling apparatus and methods

International Nuclear Information System (INIS)

2000-01-01

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is 20% for vapors or airborne particulates in the 2--3 microns range and > 50% for particles larger than 4 microns. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives

Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro

International Nuclear Information System (INIS)

Jia Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2005-01-01

During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bq kg -1 for 238 U, 0.48-93.9 Bq kg -1 for 234 U and 0.02-12.2 Bq kg -1 for 235 U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, 236 U was detectable in some of the samples. The isotopic ratios of 234 U/ 238 U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 μBq m -3 for 238 U, 0.96-38.0 μBq m -3 for 234 U, and 0.05-1.83 μBq m -3 for 235 U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBq l -1 for 238 U, 0.27-28.1 mBq l -1 for 234 U, and 0.01-0.88 mBq l -1 for 235 U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated sites in terms of

Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro.

Science.gov (United States)

Jia, Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

2005-09-01

During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bqkg(-1) for (238)U, 0.48-93.9 Bqkg(-1) for (234)U and 0.02-12.2 Bqkg(-1) for (235)U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, (236)U was detectable in some of the samples. The isotopic ratios of (234)U/(238)U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 microBqm(-3) for (238)U, 0.96-38.0 microBqm(-3) for (234)U, and 0.05-1.83 microBqm(-3) for (235)U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBql(-1) for (238)U, 0.27-28.1 mBql(-1) for (234)U, and 0.01-0.88 mBql(-1) for (235)U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated

Analysis of surfaces for characterization of fungal burden - Does it matter?

Science.gov (United States)

Viegas, Carla; Faria, Tiago; Meneses, Márcia; Carolino, Elisabete; Viegas, Susana; Gomes, Anita Quintal; Sabino, Raquel

2016-01-01

Mycological contamination of occupational environments can be a result of fungal spores' dispersion in the air and on surfaces. Therefore, it is very important to assess it in both types of the samples. In the present study we assessed fungal contamination in the air and in the surface samples to show relevance of surfaces sampling in complementing the results obtained in the air samples. In total, 42 settings were assessed by the analysis of air and surfaces samples. The settings were divided into settings with a high fungal load (7 poultry farms and 7 pig farms, 3 cork industries, 3 waste management plants, 2 wastewater treatment plants and 1 horse stable) and a low fungal load (10 hospital canteens, 8 college canteens and 1 maternity hospital). In addition to culture-based methods, molecular tools were also applied to detect fungal burden in the settings with a higher fungal load. From the 218 sampling sites, 140 (64.2%) presented different species in the examined surfaces when compared with the species identified in the air. A positive association in the high fungal load settings was found between the presence of different species in the air and surfaces. Wastewater treatment plants constituted the setting with the highest number of different species between the air and surface. We observed that surfaces sampling and application of molecular tools showed the same efficacy of species detection in high fungal load settings, corroborating the fact that surface sampling is crucial for a correct and complete analysis of occupational scenarios. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Adaptive maximal poisson-disk sampling on surfaces

KAUST Repository

Yan, Dongming

2012-01-01

In this paper, we study the generation of maximal Poisson-disk sets with varying radii on surfaces. Based on the concepts of power diagram and regular triangulation, we present a geometric analysis of gaps in such disk sets on surfaces, which is the key ingredient of the adaptive maximal Poisson-disk sampling framework. Moreover, we adapt the presented sampling framework for remeshing applications. Several novel and efficient operators are developed for improving the sampling/meshing quality over the state-of-theart. © 2012 ACM.

The use of cryogenic air sampling in the spectroscopy of airborne gamma-ray emitters

International Nuclear Information System (INIS)

Perdue, P.T.; Haywood, F.F.

1982-01-01

Wet air can be sampled over a period of four to twelve hours and, with a transfer into a special Marinelli-dewar, can be counted in a spectrometer for several hours. The present minimum detectable amount is about 4 Bq/m 3 for 222 Rn and 220 Rn with liquid air in the counting dewar equivalent to one cubic meter of ambient air. The amount of ambient air sampled can be determined from ambient pressure, temperature, and absolute humidity determinations. Standard meteorological tables are used to determine the weight of ambient air in grams/litre. This quantity divided into the net weight of liquid yields the total litres of ambient air sampled. Tests run so far with 85 Kr indicate that the noble fission gases behave in a manner similar to radon, allowing measurements of stack gases, reactor plumes, etc. The minimum detectable quantity of 85 Kr appears to be about 300 Bq/m 3 , depending upon the 222 Rn and 220 Rn content of the air

Measurements of the spatial distribution of tritium in air above a chronically contaminated surface

International Nuclear Information System (INIS)

Workman, W.J.G.; Davis, P.A.; Wood, M.J.; Barry, P.J.

1993-01-01

Tritium in air (HTO) concentrations were measured over a 13 month period above a surface that is chronically contaminated by tritium-bearing groundwater from a waste management area. The measurements were made using passive diffusion samplers, which were sited at six locations (about 100 m apart) at 0.15, 0.9, and 1.8 m above ground level. The diffusion samplers were compact, sampled at a known rate, and required no external power source. They are ideal for remote locations and require a minimum of effort to collect and analyze the data. HTO-in-air concentration peaked in the summer at 500-1500 Bq.m -3 and decreased in the winter to 1-120 Bq.m -3 . In general, concentration decreased with height above ground level, implying that HTO is being lost from the surface to the atmosphere. The flux of tritium to the atmosphere must, therefore, be taken into account to estimate the tritium mass balance for a contaminated area. (Author) 3 figs., 5 tabs., 10 refs

Analysis of surfaces for characterization of fungal burden – Does it matter?

Directory of Open Access Journals (Sweden)

Carla Viegas

2016-08-01

Full Text Available Objectives: Mycological contamination of occupational environments can be a result of fungal spores’ dispersion in the air and on surfaces. Therefore, it is very important to assess it in both types of the samples. In the present study we assessed fungal contamination in the air and in the surface samples to show relevance of surfaces sampling in complementing the results obtained in the air samples. Material and Methods: In total, 42 settings were assessed by the analysis of air and surfaces samples. The settings were divided into settings with a high fungal load (7 poultry farms and 7 pig farms, 3 cork industries, 3 waste management plants, 2 wastewater treatment plants and 1 horse stable and a low fungal load (10 hospital canteens, 8 college canteens and 1 maternity hospital. In addition to culture-based methods, molecular tools were also applied to detect fungal burden in the settings with a higher fungal load. Results: From the 218 sampling sites, 140 (64.2% presented different species in the examined surfaces when compared with the species identified in the air. A positive association in the high fungal load settings was found between the presence of different species in the air and surfaces. Wastewater treatment plants constituted the setting with the highest number of different species between the air and surface. Conclusions: We observed that surfaces sampling and application of molecular tools showed the same efficacy of species detection in high fungal load settings, corroborating the fact that surface sampling is crucial for a correct and complete analysis of occupational scenarios.

Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

Science.gov (United States)

Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

2016-01-01

This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

Temporal Changes in the Observed Relationship between Cloud Cover and Surface Air Temperature.

Science.gov (United States)

Sun, Bomin; Groisman, Pavel Ya.; Bradley, Raymond S.; Keimig, Frank T.

2000-12-01

The relationship between cloud cover and near-surface air temperature and its decadal changes are examined using the hourly synoptic data for the past four to six decades from five regions of the Northern Hemisphere: Canada, the United States, the former Soviet Union, China, and tropical islands of the western Pacific. The authors define the normalized cloud cover-surface air temperature relationship, NOCET or dT/dCL, as a temperature anomaly with a unit (one-tenth) deviation of total cloud cover from its average value. Then mean monthly NOCET time series (night- and daytime, separately) are area-averaged and parameterized as functions of surface air humidity and snow cover. The day- and nighttime NOCET variations are strongly anticorrelated with changes in surface humidity. Furthermore, the daytime NOCET changes are positively correlated to changes in snow cover extent. The regionally averaged nighttime NOCET varies from 0.05 K tenth1 in the wet Tropics to 1.0 K tenth1 at midlatitudes in winter. The daytime regional NOCET ranges from 0.4 K tenth1 in the Tropics to 0.7 K tenth1 at midlatitudes in winter.The authors found a general strengthening of a daytime surface cooling during the post-World War II period associated with cloud cover over the United States and China, but a minor reduction of this cooling in higher latitudes. Furthermore, since the 1970s, a prominent increase in atmospheric humidity has significantly weakened the effectiveness of the surface warming (best seen at nighttime) associated with cloud cover.The authors apportion the spatiotemporal field of interactions between total cloud cover and surface air temperature into a bivariate relationship (described by two equations, one for daytime and one for nighttime) with surface air humidity and snow cover and two constant factors. These factors are invariant in space and time domains. It is speculated that they may represent empirical estimates of the overall cloud cover effect on the surface air

Sampling for Beryllium Surface Contamination using Wet, Dry and Alcohol Wipe Sampling

Energy Technology Data Exchange (ETDEWEB)

Kerr, Kent [Central Missouri State Univ., Warrensburg, MO (United States)

2004-12-01

This research project was conducted at the National Nuclear Security Administration's Kansas City Plant, operated by Honeywell Federal Manufacturing and Technologies, in conjunction with the Safety Sciences Department of Central Missouri State University, to compare relative removal efficiencies of three wipe sampling techniques currently used at Department of Energy facilities. Efficiencies of removal of beryllium contamination from typical painted surfaces were tested by wipe sampling with dry Whatman 42 filter paper, with water-moistened (Ghost Wipe) materials, and by methanol-moistened wipes. Test plates were prepared using 100 mm X 15 mm Pyrex Petri dishes with interior surfaces spray painted with a bond coat primer. To achieve uniform deposition over the test plate surface, 10 ml aliquots of solution containing 1 beryllium and 0.1 ml of metal working fluid were transferred to the test plates and subsequently evaporated. Metal working fluid was added to simulate the slight oiliness common on surfaces in metal working shops where fugitive oil mist accumulates over time. Sixteen test plates for each wipe method (dry, water, and methanol) were processed and sampled using a modification of wiping patterns recommended by OSHA Method 125G. Laboratory and statistical analysis showed that methanol-moistened wipe sampling removed significantly more (about twice as much) beryllium/oil-film surface contamination as water-moistened wipes (p< 0.001), which removed significantly more (about twice as much) residue as dry wipes (p <0.001). Evidence for beryllium sensitization via skin exposure argues in favor of wipe sampling with wetting agents that provide enhanced residue removal efficiency.

Sampling of power plant stacks for air toxic emissions: Topical report for Phases 1 and 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-21

Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions.

Use of a Radon Stripping Algorithm for Retrospective Assessment of Air Filter Samples

International Nuclear Information System (INIS)

Hayes, Robert

2009-01-01

An evaluation of a large number of air sample filters was undertaken using a commercial alpha and beta spectroscopy system employing a passive implanted planar silicon (PIPS) detector. Samples were only measured after air flow through the filters had ceased. Use of a commercial radon stripping algorithm was implemented to discriminate anthropogenic alpha and beta activity on the filters from the radon progeny. When uncontaminated air filters were evaluated, the results showed that there was a time-dependent bias in both average estimates and measurement dispersion with the relative bias being small compared to the dispersion. By also measuring environmental air sample filters simultaneously with electroplated alpha and beta sources, use of the radon stripping algorithm demonstrated a number of substantial unexpected deviations. Use of the current algorithm is therefore not recommended for assay applications and so use of the PIPS detector should only be utilized for gross counting without appropriate modifications to the curve fitting algorithm. As a screening method, the radon stripping algorithm might be expected to see elevated alpha and beta activities on air sample filters (not due to radon progeny) around the 200 dpm level

EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

Directory of Open Access Journals (Sweden)

V. V. Kuzin

2018-01-01

Full Text Available The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC, Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used

Sample and injection manifolds used to in-place test of nuclear air-cleaning system

International Nuclear Information System (INIS)

Qiu Dangui; Li Xinzhi; Hou Jianrong; Qiao Taifei; Wu Tao; Zhang Jirong; Han Lihong

2012-01-01

Objective: According to the regulations of nuclear safety rules and related standards, in-place test of the nuclear air-cleaning systems should be carried out before and during operation of the nuclear facilities, which ensure them to be in good condition. In some special conditions, the use of sample and injection manifolds is required to make the test tracer and ventilating duct air fully mixed, so as to get the on-spot typical sample. Methods: This paper introduces the technology and application of the sample and injection manifolds in nuclear air-cleaning system. Results: Multi point injection and multi point sampling technology as an effective experimental method, has been used in a of domestic and international nuclear facilities. Conclusion: The technology solved the problem of uniformly of on-spot injection and sampling,which plays an important role in objectively evaluating the function of nuclear air-cleaning system. (authors)

Surface deposition measurements of the TMI-2 gross decontamination experiment

International Nuclear Information System (INIS)

McIssac, C.V.; Hetzer, D.C.

1982-01-01

In order to measure the effectiveness of the gross decontamination experiment (principally a water spray technique) performed in the TMI-2 reactor building, the Technical Information and Examination Program's Radiation and Environment personnel made surface activity measurements before and after the experiment. In conjunction with surface sampling, thermoluminescent dosimeter (TLD) and gamma spectrometry measurements were also performed to distinguish between radiation fields and contamination. The surface sampler used to collect samples from external surfaces within the reactor building is a milling tool having four major components: a 1.27-cm constant-speed drill; a drill support assembly that allows setting sample penetration depth; filter cartridges for intake air purification and sample collection; and an air pump that forces air across the surface being sampled and through the sample filter cartridge

Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

Czech Academy of Sciences Publication Activity Database

Sáňka, O.; Melymuk, L.; Čupr, P.; Dvorská, Alice; Klánová, J.

2014-01-01

Roč. 90, oct (2014), s. 88-95 ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : passive air sampling * air dispersion modeling * GIS * polycyclic aromatic hydrocarbons * emission inventories Subject RIV: DI - Air Pollution ; Quality Impact factor: 3.281, year: 2014

High-throughput liquid-absorption air-sampling apparatus and methods

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-11

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is < 10 cm of water, usually < 5 cm of water. The sampler's collection efficiency is usually > 20% for vapors or airborne particulates in the 2--3 microns range and > 50% for particles larger than 4 microns. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

The contribution to surface dose form air scatter in mega voltage photon beams

International Nuclear Information System (INIS)

Carolan, M.G.; Butson, M.; Metcalfe, P.

1996-01-01

Full text: The minimisation of surface dose is an important requirement in radiotherapy in order to avoid undesirable skin reactions. For this reason significant effort has been expended to avoid and understand photon and electron scatter in the heads of linear accelerators which may contribute to surface dose. In this study we have examined the contribution to surface dose which arises due to scatter in the air above the patient. Experimental investigations of air contributions are difficult to design and execute. Therefore we have used Monte Carlo calculations to determine the effect that the presence of air has on surface dose. Methods: The Los Alamos Monte Carlo Neutron and Photon transport code, MCNP4A which incorporates the ETRAN electron transport code from the Integrated TIGER Series of codes was used for our simulations. The geometry used in the model was a 30 cm cube of water. The dose was tallied in cylindrical elements of 7 cm diameter along the axis of the photon beam. For the first millimetre along the beam axis in the phantom, the dose was determined at 0.1 mm increments in 0.1 mm thick volumes. For depths between 1.0 mm and 15.0 mm the dose was determined every 1 mm in 1 mm cylindrical volumes. This yields a depth dose profile with fine spatial resolution near the phantom surface. Dose was also tallied at depths of 5.0, 10.0, 15.0 and 20.0 cm. The simulations were done assuming a 6 MV photon source with a diameter of 1.5 cm, a gaussian intensity profile and a photon energy spectrum based on Mohan et al. (Med. Phys. 12 (1985) 592). No accelerator head geometry was modelled. The field size was defined by virtual collimators which were simply thin regions of zero photon importance and therefore do not contribute to photon or electron scatter. All simulations were run for sufficient particle histories (∼2x10 7 - 5x10 7 source photons) to give statistical uncertainties of ≤ 10% and in most cases ≤ 5%. Fields of size 10, 15, 20 and 25 cm were used

Sampling free energy surfaces as slices by combining umbrella sampling and metadynamics.

Science.gov (United States)

Awasthi, Shalini; Kapil, Venkat; Nair, Nisanth N

2016-06-15

Metadynamics (MTD) is a very powerful technique to sample high-dimensional free energy landscapes, and due to its self-guiding property, the method has been successful in studying complex reactions and conformational changes. MTD sampling is based on filling the free energy basins by biasing potentials and thus for cases with flat, broad, and unbound free energy wells, the computational time to sample them becomes very large. To alleviate this problem, we combine the standard Umbrella Sampling (US) technique with MTD to sample orthogonal collective variables (CVs) in a simultaneous way. Within this scheme, we construct the equilibrium distribution of CVs from biased distributions obtained from independent MTD simulations with umbrella potentials. Reweighting is carried out by a procedure that combines US reweighting and Tiwary-Parrinello MTD reweighting within the Weighted Histogram Analysis Method (WHAM). The approach is ideal for a controlled sampling of a CV in a MTD simulation, making it computationally efficient in sampling flat, broad, and unbound free energy surfaces. This technique also allows for a distributed sampling of a high-dimensional free energy surface, further increasing the computational efficiency in sampling. We demonstrate the application of this technique in sampling high-dimensional surface for various chemical reactions using ab initio and QM/MM hybrid molecular dynamics simulations. Further, to carry out MTD bias reweighting for computing forward reaction barriers in ab initio or QM/MM simulations, we propose a computationally affordable approach that does not require recrossing trajectories. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Sampling and chemical analysis in environmental samples around Nuclear Power Plants and some environmental samples

Energy Technology Data Exchange (ETDEWEB)

Cho, Yong Woo; Han, Man Jung; Cho, Seong Won; Cho, Hong Jun; Oh, Hyeon Kyun; Lee, Jeong Min; Chang, Jae Sook [KORTIC, Taejon (Korea, Republic of)

2002-12-15

Twelve kinds of environmental samples such as soil, seawater, underground water, etc. around Nuclear Power Plants(NPPs) were collected. Tritium chemical analysis was tried for the samples of rain water, pine-needle, air, seawater, underground water, chinese cabbage, a grain of rice and milk sampled around NPPs, and surface seawater and rain water sampled over the country. Strontium in the soil that sere sampled at 60 point of district in Korea were analyzed. Tritium were sampled at 60 point of district in Korea were analyzed. Tritium were analyzed in 21 samples of surface seawater around the Korea peninsular that were supplied from KFRDI(National Fisheries Research and Development Institute). Sampling and chemical analysis environmental samples around Kori, Woolsung, Youngkwang, Wooljin Npps and Taeduk science town for tritium and strontium analysis was managed according to plans. Succeed to KINS after all samples were tried.

Sampling and preparation of air pollutants at the Coal Paiton Power Plant area Probolinggo

International Nuclear Information System (INIS)

Iswantoro; Sutanto, W.W

2013-01-01

Sampling has been conducted on April 8 th to 18 th, 2012 at the plant area of Paiton Coal Power Plant using e-sampler for particulated matter PM-2,5 and PM-10, high volume air sampler for total suspended particulate (TSP) at the three sampling locations as the representative pollution. Filter before and after sampling was weighed and extremely guarded contamination. Air filters stored in desiccator filter for 24 hours. Determination of concentration of ambient air pollutants conducted by gravimetric method derived from a reduction in weight the samples on the filter PM-2,5; PM-10 and TSP to the weight of the empty filter. (author)

Development and validation of a highly sensitive gas chromatographic-mass spectrometric screening method for the simultaneous determination of nanogram levels of fentanyl, sufentanil and alfentanil in air and surface contamination wipes.

Science.gov (United States)

Van Nimmen, Nadine F J; Veulemans, Hendrik A F

2004-05-07

A highly sensitive gas chromatographic-mass spectrometric (GC-MS) analytical method for the determination of the opioid narcotics fentanyl, alfentanil, and sufentanil in industrial hygiene personal air samples and surface contamination wipes was developed and comprehensively validated. Sample preparation involved a single step extraction of the samples with methanol, fortified with a fixed amount of the penta-deuterated analogues of the opioid narcotics as internal standard. The GC-MS analytical procedure using selected ion monitoring (SIM) was shown to be highly selective. Linearity was shown for levels of extracted wipe and air samples corresponding to at least 0.1-2 times their surface contamination limit (SCL) and accordingly to 0.1-2 times their time weighted average occupational exposure limit (OEL-TWA) based on a full shift 9601 air sample. Extraction recoveries were determined for spiked air samples and surface wipes and were found to be quantitative for both sampling media in the entire range studied. The air sampling method's limit of detection (LOD) was determined to be 0.4 ng per sample for fentanyl and sufentanil and 1.6 ng per sample for alfentanil, corresponding to less than 1% of their individual OEL for a full shift air sample (9601). The limit of quantification (LOQ) was found to be 1.4, 1.2, and 5.0 ng per filter for fentanyl, sufentanil, and alfentanil, respectively. The wipe sampling method had LODs of 4 ng per wipe for fentanyl and sufentanil and 16 ng per wipe for alfentanil and LOQs of respectively, 14, 12, and 50 ng per wipe. The analytical intra-assay precision of the air sampling and wipe sampling method, defined as the coefficient of variation on the analytical result of six replicate spiked media was below 10 and 5%, respectively, for all opioids at all spike levels. Accuracy expressed as relative error was determined to be below 10%, except for alfentanil at the lowest spike level (-13.1%). The stability of the opioids during simulated

Measurement of the carbon 14 activity at natural level in air samples

International Nuclear Information System (INIS)

Olivier, A.; Tenailleau, L.; Baron, Y.; Maro, D.

2004-01-01

The aim of the study was to measure the carbon 14 activity at natural level in air samples using classical methods of radiochemistry and beta counting. Three different methods have been tested in order to minimise the detection limit. In the three methods, the first step consists in trapping the atmospheric carbon 14 into NaOH (1N) using a bubbling chamber. The atmospheric carbon dioxide reacts with NaOH to form Na 2 CO 3 . In the first method the Na 2 CO 3 solution is mixed with a liquid scintillate and is directly analysed by liquid scintillation counting (LSC). The detection limit is approximately 1 Bq/m 3 of air samples. The second method consists in evaporating the carbonate solution and then counting the solid residue with a proportional gas circulation counter. The detection limit obtained is lower than the first method (0.4 Bq/m 3 of air samples). In the third method, Na 2 CO 3 is precipitated into CaCO 3 in presence of CaCl 2 . CaCO 3 is then analysed by LSC. This method appear to be the most appropriate, the detection limit is 0.05 Bq/m 3 of air samples. (author)

Is there an association between airborne and surface microbes in the critical care environment?

Science.gov (United States)

Smith, J; Adams, C E; King, M F; Noakes, C J; Robertson, C; Dancer, S J

2018-04-09

There are few data and no accepted standards for air quality in the intensive care unit (ICU). Any relationship between airborne pathogens and hospital-acquired infection (HAI) risk in the ICU remains unknown. First, to correlate environmental contamination of air and surfaces in the ICU; second, to examine any association between environmental contamination and ICU-acquired staphylococcal infection. Patients, air, and surfaces were screened on 10 sampling days in a mechanically ventilated 10-bed ICU for a 10-month period. Near-patient hand-touch sites (N = 500) and air (N = 80) were screened for total colony count and Staphylococcus aureus. Air counts were compared with surface counts according to proposed standards for air and surface bioburden. Patients were monitored for ICU-acquired staphylococcal infection throughout. Overall, 235 of 500 (47%) surfaces failed the standard for aerobic counts (≤2.5 cfu/cm 2 ). Half of passive air samples (20/40: 50%) failed the 'index of microbial air' contamination (2 cfu/9 cm plate/h), and 15/40 (37.5%) active air samples failed the clean air standard (<10 cfu/m 3 ). Settle plate data were closer to the pass/fail proportion from surfaces and provided the best agreement between air parameters and surfaces when evaluating surface benchmark values of 0-20 cfu/cm 2 . The surface standard most likely to reflect hygiene pass/fail results compared with air was 5 cfu/cm 2 . Rates of ICU-acquired staphylococcal infection were associated with surface counts per bed during 72h encompassing sampling days (P = 0.012). Passive air sampling provides quantitative data analogous to that obtained from surfaces. Settle plates could serve as a proxy for routine environmental screening to determine the infection risk in ICU. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow

DEFF Research Database (Denmark)

Delfs, Jens Olaf; Wang, Wenqing; Kalbacher, Thomas

2013-01-01

wave) shallow flow and two-phase flow in a porous medium. The simultaneous mass transfer between the soil, overland, and atmosphere compartments is achieved by upgrading a fully established leakance concept for overland-soil liquid exchange to an air exchange flux between soil and atmosphere. In a new...... algorithm, leakances operate as a valve for gas pressure in a liquid-covered porous medium facilitating the simulation of air out-break events through the land surface. General criteria are stated to guarantee stability in a sequential iterative coupling algorithm and, in addition, for leakances to control...

Air sampling by pumping through a filter: effects of air flow rate, concentration, and decay of airborne substances

OpenAIRE

Šoštarić, Marko; Petrinec, Branko; Babić, Dinko

2016-01-01

This paper tackles the issue of interpreting the number of airborne particles adsorbed on a filter through which a certain volume of sampled air has been pumped. This number is equal to the product of the pumped volume and particle concentration in air, but only if the concentration is constant over time and if there is no substance decomposition on the filter during sampling. If this is not the case, one must take into account the inconstancy of the concentration and the decay law for a give...

Evaluation of surface sampling method performance for Bacillus Spores on clean and dirty outdoor surfaces.

Energy Technology Data Exchange (ETDEWEB)

Wilson, Mollye C.; Einfeld, Wayne; Boucher, Raymond M.; Brown, Gary Stephen; Tezak, Matthew Stephen

2011-06-01

Recovery of Bacillus atrophaeous spores from grime-treated and clean surfaces was measured in a controlled chamber study to assess sampling method performance. Outdoor surfaces investigated by wipe and vacuum sampling methods included stainless steel, glass, marble and concrete. Bacillus atrophaeous spores were used as a surrogate for Bacillus anthracis spores in this study designed to assess whether grime-coated surfaces significantly affected surface sampling method performance when compared to clean surfaces. A series of chamber tests were carried out in which known amounts of spores were allowed to gravitationally settle onto both clean and dirty surfaces. Reference coupons were co-located with test coupons in all chamber experiments to provide a quantitative measure of initial surface concentrations of spores on all surfaces, thereby allowing sampling recovery calculations. Results from these tests, carried out under both low and high humidity conditions, show that spore recovery from grime-coated surfaces is the same as or better than spore recovery from clean surfaces. Statistically significant differences between method performance for grime-coated and clean surfaces were observed in only about half of the chamber tests conducted.

Stratospheric Air Sub-sampler (SAS) and its application to analysis of Delta O-17(CO2) from small air samples collected with an AirCore

NARCIS (Netherlands)

Mrozek, Dorota Janina; van der Veen, Carina; Hofmann, Magdalena E. G.; Chen, Huilin; Kivi, Rigel; Heikkinen, Pauli; Rockmann, Thomas

2016-01-01

We present the set-up and a scientific application of the Stratospheric Air Sub-sampler (SAS), a device to collect and to store the vertical profile of air collected with an AirCore (Karion et al., 2010) in numerous sub-samples for later analysis in the laboratory. The SAS described here is a 20m

Effects of XPS operational parameters on investigated sample surfaces

International Nuclear Information System (INIS)

Mrad, O.; Ismail, I.

2013-04-01

In this work, we studied the effects of the operating conditions of the xray photoelectron spectroscopy analysis technique (XPS) on the investigated samples. Firstly, the performances of the whole system have been verified as well as the accuracy of the analysis. Afterwards, the problem of the analysis of insulating samples caused by the charge buildup on the surface has been studied. The use of low-energy electron beam (<100 eV) to compensate the surface charge has been applied. The effect of X-ray on the samples have been assessed and was found to be nondestructive within the analysis time. The effect of low- and high-energy electron beams on the sample surface have been investigated. Highenergy electrons were found to have destructive effect on organic samples. The sample heating procedure has been tested and its effect on the chemical stat of the surface was followed. Finally, the ion source was used to determine the elements distribution and the chemical stat of different depths of the sample. A method has been proposed to determine these depths (author).

Influence of air-powder polishing on bond strength and surface-free energy of universal adhesive systems.

Science.gov (United States)

Tamura, Yukie; Takamizawa, Toshiki; Shimamura, Yutaka; Akiba, Shunsuke; Yabuki, Chiaki; Imai, Arisa; Tsujimoto, Akimasa; Kurokawa, Hiroyasu; Miyazaki, Masashi

2017-11-29

The influences of air-powder polishing with glycine or sodium bicarbonate powders on shear bond strengths (SBS) and surface-free energies of universal adhesives were examined. Scotchbond Universal Adhesive (SU, 3M ESPE), G-Premio Bond (GP, GC), Adhese Universal (AU, Ivoclar Vivadent), and All-Bond Universal (AB, Bisco) were used in this study. Bovine dentin surfaces were air polished with glycine or sodium bicarbonate powders prior to the bonding procedure, and resin pastes were bonded to the dentin surface using universal adhesives. SBSs were determined after 24-h storage in distilled water at 37°C. Surface-free energy was then determined by measuring contact angles using three test liquids on dentin surfaces. Significantly lower SBSs were observed for dentin that was air-powder polished and surface-free energies were concomitantly lowered. This study indicated that air-powder polishing influences SBSs and surface-free energies. However, glycine powder produced smaller changes in these surface parameters than sodium bicarbonate.

Air-sampling inlet contamination by aircraft emissions on the NASA CV-990 aircraft

Science.gov (United States)

Condon, E. P.; Vedder, J. F.

1984-01-01

Results of an experimental investigation of the contamination of air sampling inlets by aircraft emissions from the NASA CV-990 research aircraft are presented. This four-engine jet aircraft is a NASA facility used for many different atmospheric and meteorological experiments, as well as for developing spacecraft instrumentation for remote measurements. Our investigations were performed to provide information on which to base the selection of sampling locations for a series of multi-instrument missions for measuring tropospheric trace gases. The major source of contamination is the exhaust from the jet engines, which generate many of the same gases that are of interest in atmospheric chemistry, as well as other gases that may interfere with sampling measurements. The engine exhaust contains these gases in mixing ratios many orders of magnitude greater than those that occur in the clean atmosphere which the missions seek to quantify. Pressurized samples of air were collected simultaneously from a scoop located forward of the engines to represent clean air and from other multiport scoops at various aft positions on the aircraft. The air samples were analyzed in the laboratory by gas chromatography for carbon monoxide, an abundant combustion by-product. Data are presented for various scoop locations under various flight conditions.

Statistics of surface divergence and their relation to air-water gas transfer velocity

Science.gov (United States)

Asher, William E.; Liang, Hanzhuang; Zappa, Christopher J.; Loewen, Mark R.; Mukto, Moniz A.; Litchendorf, Trina M.; Jessup, Andrew T.

2012-05-01

Air-sea gas fluxes are generally defined in terms of the air/water concentration difference of the gas and the gas transfer velocity,kL. Because it is difficult to measure kLin the ocean, it is often parameterized using more easily measured physical properties. Surface divergence theory suggests that infrared (IR) images of the water surface, which contain information concerning the movement of water very near the air-water interface, might be used to estimatekL. Therefore, a series of experiments testing whether IR imagery could provide a convenient means for estimating the surface divergence applicable to air-sea exchange were conducted in a synthetic jet array tank embedded in a wind tunnel. Gas transfer velocities were measured as a function of wind stress and mechanically generated turbulence; laser-induced fluorescence was used to measure the concentration of carbon dioxide in the top 300 μm of the water surface; IR imagery was used to measure the spatial and temporal distribution of the aqueous skin temperature; and particle image velocimetry was used to measure turbulence at a depth of 1 cm below the air-water interface. It is shown that an estimate of the surface divergence for both wind-shear driven turbulence and mechanically generated turbulence can be derived from the surface skin temperature. The estimates derived from the IR images are compared to velocity field divergences measured by the PIV and to independent estimates of the divergence made using the laser-induced fluorescence data. Divergence is shown to scale withkLvalues measured using gaseous tracers as predicted by conceptual models for both wind-driven and mechanically generated turbulence.

Correlation and uncertainties evaluation in backscattering of entrance surface air kerma measurements

Energy Technology Data Exchange (ETDEWEB)

Teixeira, G.J.; Sousa, C.H.S.; Peixoto, J.G.P., E-mail: gt@ird.gov.br [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

The air kerma measurement is important to verify the applied doses in radiodiagnostic. The literature determines some methods to measure the entrance surface air kerma or entrance surface dose but some of this methods may increase the measurement with the backscattering. Were done setups of measurements to do correlations between them. The expanded uncertainty exceeded 5% for measurements with backscattering, reaching 8.36%, while in situations where the backscattering was avoided, the uncertainty was 3.43%. (author)

Analysis of tree bark samples for air pollution biomonitoring of an urban area

International Nuclear Information System (INIS)

Martins, Ana Paula G.; Negri, Elnara M.; Saldiva, Paulo H.N.

2009-01-01

Air pollution is receiving much attention as a public health problem around the world due to its adverse health effects from exposures by urban populations. Within this context, the use of vegetal biomonitoring to evaluate air quality has been investigated throughout the world. Air pollutant levels are high in the city of Sao Paulo, SP, Brazil and being the vehicle emissions its main source. The aim of this study was to evaluate concentrations of As, Ba, Br, Ca, Co, Cr, Cu, Fe, Mn, Pb, S, Sb and Zn in tree bark samples used as biomonitor of urban air pollution. Concentrations of these elements were determined in barks collected in trees of the Ibirapuera Park, one of the biggest and most visited parks of the city of Sao Paulo city. Samples of tree barks were also collected in a site outside the city of Sao Paulo, in a rural area of Embu-Guacu, considered as a control site. The element concentrations were determined by the methods of Instrumental Neutron Activation Analysis (INAA) and of Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The findings of this study showed that tree bark samples may be used as biomonitors of urban air pollution in a micro scale, and both techniques, INAA and EDXRF, can be used to evaluate element concentrations in tree bark samples. (author)

Numerical investigation of mist/air impingement cooling on ribbed blade leading-edge surface.

Science.gov (United States)

Bian, Qingfei; Wang, Jin; Chen, Yi-Tung; Wang, Qiuwang; Zeng, Min

2017-12-01

The working gas turbine blades are exposed to the environment of high temperature, especially in the leading-edge region. The mist/air two-phase impingement cooling has been adopted to enhance the heat transfer on blade surfaces and investigate the leading-edge cooling effectiveness. An Euler-Lagrange particle tracking method is used to simulate the two-phase impingement cooling on the blade leading-edge. The mesh dependency test has been carried out and the numerical method is validated based on the available experimental data of mist/air cooling with jet impingement on a concave surface. The cooling effectiveness on three target surfaces is investigated, including the smooth and the ribbed surface with convex/concave columnar ribs. The results show that the cooling effectiveness of the mist/air two-phase flow is better than that of the single-phase flow. When the ribbed surfaces are used, the heat transfer enhancement is significant, the surface cooling effectiveness becomes higher and the convex ribbed surface presents a better performance. With the enhancement of the surface heat transfer, the pressure drop in the impingement zone increases, but the incremental factor of the flow friction is smaller than that of the heat transfer enhancement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surface Treatment of PEOT/PBT (55/45 with a Dielectric Barrier Discharge in Air, Helium, Argon and Nitrogen at Medium Pressure

Directory of Open Access Journals (Sweden)

Pieter Cools

2018-03-01

Full Text Available This work describes the surface modification of 300PEO-PEOT/PBT 55/45 thin films using a medium pressure dielectric barrier discharge system operated in argon, helium, nitrogen or dry air to improve cell-surface interactions of this established biomaterial. The first part of the paper describes the optimization of the plasma processing parameters using water contact angle goniometry. The optimized samples are then characterized for changes in surface topography and surface chemical composition using atomic force microscopy (AFM and X-ray fluorescence spectroscopy (XPS respectively. For all plasma treatments, a pronounced increase in surface wettability was observed, of which the extent is dependent on the used plasma discharge gas. Except for dry air, only minor changes in surface topography were noted, while XPS confirmed that the changes in wettability were mainly chemical in nature with the incorporation of 5–10% of extra oxygen as a variety of polar groups. Similarly, for the nitrogen plasma, 3.8% of nitrogen polar groups were additionally incorporated. Human foreskin fibroblast (HFF in vitro analysis showed that within the first 24 h after cell seeding, the effects on cell-surface interactivity were highly dependent on the used discharge gas, nitrogen plasma treatment being the most efficient. Differences between untreated and plasma-treated samples were less pronounced compared to other biodegradable materials, but a positive influence on cell adhesion and proliferation was still observed.

Influence of warm air-drying on enamel bond strength and surface free-energy of self-etch adhesives.

Science.gov (United States)

Shiratsuchi, Koji; Tsujimoto, Akimasa; Takamizawa, Toshiki; Furuichi, Tetsuya; Tsubota, Keishi; Kurokawa, Hiroyasu; Miyazaki, Masashi

2013-08-01

We examined the effect of warm air-drying on the enamel bond strengths and the surface free-energy of three single-step self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and then wet ground with #600 silicon carbide (SiC) paper. The adhesives were applied according to the instructions of the respective manufacturers and then dried in a stream of normal (23°C) or warm (37°C) air for 5, 10, and 20 s. After visible-light irradiation of the adhesives, resin composites were condensed into a mold and polymerized. Ten samples per test group were stored in distilled water at 37°C for 24 h and then the bond strengths were measured. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The enamel bond strengths varied according to the air-drying time and ranged from 15.8 to 19.1 MPa. The trends for the bond strengths were different among the materials. The value of the γS⁺ component increased slightly when drying was performed with a stream of warm air, whereas that of the γS⁻ component decreased significantly. These data suggest that warm air-drying is essential to obtain adequate enamel bond strengths, although increasing the drying time did not significantly influence the bond strength. © 2013 Eur J Oral Sci.

Composite sampling of a Bacillus anthracis surrogate with cellulose sponge surface samplers from a nonporous surface.

Directory of Open Access Journals (Sweden)

Jenia A M Tufts

Full Text Available A series of experiments was conducted to explore the utility of composite-based collection of surface samples for the detection of a Bacillus anthracis surrogate using cellulose sponge samplers on a nonporous stainless steel surface. Two composite-based collection approaches were evaluated over a surface area of 3716 cm2 (four separate 929 cm2 areas, larger than the 645 cm2 prescribed by the standard Centers for Disease Control (CDC and Prevention cellulose sponge sampling protocol for use on nonporous surfaces. The CDC method was also compared to a modified protocol where only one surface of the sponge sampler was used for each of the four areas composited. Differences in collection efficiency compared to positive controls and the potential for contaminant transfer for each protocol were assessed. The impact of the loss of wetting buffer from the sponge sampler onto additional surface areas sampled was evaluated. Statistical tests of the results using ANOVA indicate that the collection of composite samples using the modified sampling protocol is comparable to the collection of composite samples using the standard CDC protocol (p  =  0.261. Most of the surface-bound spores are collected on the first sampling pass, suggesting that multiple passes with the sponge sampler over the same surface may be unnecessary. The effect of moisture loss from the sponge sampler on collection efficiency was not significant (p  =  0.720 for both methods. Contaminant transfer occurs with both sampling protocols, but the magnitude of transfer is significantly greater when using the standard protocol than when the modified protocol is used (p<0.001. The results of this study suggest that composite surface sampling, by either method presented here, could successfully be used to increase the surface area sampled per sponge sampler, resulting in reduced sampling times in the field and decreased laboratory processing cost and turn-around times.

AirSWOT Measurements of Water Surface Elevations and Hydraulic Gradients over the Yukon Flats, Alaska

Science.gov (United States)

Pitcher, L. H.; Pavelsky, T.; Smith, L. C.; Moller, D.; Altenau, E. H.; Lion, C.; Bertram, M.; Cooley, S. W.

2017-12-01

AirSWOT is an airborne, Ka-band synthetic aperture radar interferometer (InSAR) intended to quantify surface water fluxes by mapping water surface elevations (WSE). AirSWOT will also serve as a calibration/validation tool for the Surface Water and Ocean Topography (SWOT) satellite mission (scheduled for launch in 2021). The hydrology objectives for AirSWOT and SWOT are to measure WSE with accuracies sufficient to estimate hydrologic fluxes in lakes, wetlands and rivers. However, current understanding of the performance of these related though not identical instruments when applied to complex river-lake-wetland fluvial environments remains predominantly theoretical. We present AirSWOT data acquired 15-June-2015 over the Yukon Flats, Alaska, USA, together with in situ field surveys, to assess the accuracy of AirSWOT WSE measurements in lakes and rivers. We use these data to demonstrate that AirSWOT can be used to estimate large-scale hydraulic gradients across wetland complexes. Finally, we present key lessons learned from this AirSWOT analysis for consideration in future campaigns, including: maximizing swath overlap for spatial averaging to minimize uncertainty as well as orienting flight paths parallel to river flow directions to reduce along track aircraft drift for neighboring flight paths. We conclude that spatially dense AirSWOT measurements of river and lake WSEs can improve geospatial understanding of surface water hydrology and fluvial processes.

ARIMA representation for daily solar irradiance and surface air temperature time series

Science.gov (United States)

Kärner, Olavi

2009-06-01

Autoregressive integrated moving average (ARIMA) models are used to compare long-range temporal variability of the total solar irradiance (TSI) at the top of the atmosphere (TOA) and surface air temperature series. The comparison shows that one and the same type of the model is applicable to represent the TSI and air temperature series. In terms of the model type surface air temperature imitates closely that for the TSI. This may mean that currently no other forcing to the climate system is capable to change the random walk type variability established by the varying activity of the rotating Sun. The result should inspire more detailed examination of the dependence of various climate series on short-range fluctuations of TSI.

Global Validation of MODIS Atmospheric Profile-Derived Near-Surface Air Temperature and Dew Point Estimates

Science.gov (United States)

Famiglietti, C.; Fisher, J.; Halverson, G. H.

2017-12-01

This study validates a method of remote sensing near-surface meteorology that vertically interpolates MODIS atmospheric profiles to surface pressure level. The extraction of air temperature and dew point observations at a two-meter reference height from 2001 to 2014 yields global moderate- to fine-resolution near-surface temperature distributions that are compared to geographically and temporally corresponding measurements from 114 ground meteorological stations distributed worldwide. This analysis is the first robust, large-scale validation of the MODIS-derived near-surface air temperature and dew point estimates, both of which serve as key inputs in models of energy, water, and carbon exchange between the land surface and the atmosphere. Results show strong linear correlations between remotely sensed and in-situ near-surface air temperature measurements (R2 = 0.89), as well as between dew point observations (R2 = 0.77). Performance is relatively uniform across climate zones. The extension of mean climate-wise percent errors to the entire remote sensing dataset allows for the determination of MODIS air temperature and dew point uncertainties on a global scale.

Assessment of broiler surface temperature variation when exposed to different air temperatures

Directory of Open Access Journals (Sweden)

GR Nascimento

2011-12-01

Full Text Available This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST of 7- to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb® broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 ºC to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05 from the values obtained by the equations. MST values significantly increased (p < 0.05 when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

Processes of Ammonia Air-Surface Exchange in a Fertilized Zea Mays Canopy

Science.gov (United States)

Recent incorporation of coupled soil biogeochemical and bi-directional NH3 air-surface exchange algorithms into regional air quality models holds promise for further reducing uncertainty in estimates of NH3 emissions from fertilized soils. While this advancement represents a sig...

Recommended radiological air sampling and internal contamination control at nuclear power plants

International Nuclear Information System (INIS)

Rich, B.L.; Ritter, P.D.; Martz, D.E.

1984-01-01

It has long been recognized by the NRC Technical Staffs that estimating the quantity of radioactivity inhaled by an individual worker involved large uncertainties. General air samples usually produce concentrations lower than those in the workers Breathing Zone (BZ). NRC guides have recognized this problem by specifying air monitoring programs which sample the Breathing Zone or concentrations known to be higher than that actually inhaled. In addition the availability of suitable samplers to obtain BZ samples and the practicality of requiring their use was somewhat in question to the NRC technical staff. AN NRC development contract was issued to provide a detailed review of the technical aspects of the problems and recommendations for practical upgrade of federal guidance. This project accomplished a review of the nuclear industry experience and knowledge through a literature search, site visits to representative licensed facilities, telephone surveys of many others, laboratory testing of personal air samplers (lapel samplers) and aerosol diffusion experiments to verify key conclusions and assumptions

A study of laser surface modification of polymers: A comparison in air and water

DEFF Research Database (Denmark)

Marla, Deepak; Andersen, Sebastian A.; Zhang, Yang

2018-01-01

Laser surface modification is a technique to modify polymer surfaces for various applications. In our earlier work [Physics Procedia, 83:211–217, 2016], we showed that when the laser surface modification process was carried out in water instead of air, the obtained surface characteristics were...... research. The observed images of laser modified surfaces suggest that a hemispherical hump is formed in the case of water at lower laser fluences that breakup with an increase in fluence. Such a behavior was not observed when the process was carried out in air. We explain this phenomenon by simulating...

Effect of sample digestion, air filter contamination, and post-adsorption on the analysis of trace elements in air particulate matter

International Nuclear Information System (INIS)

Yang, Xiao Jin; Wan, Pingyu; Foley, Roy

2012-01-01

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma MS are the major analytical tools for trace elements in environmental matrices, however, the underestimate of certain trace elements in analysis of air particulate matter by these two techniques has long been observed. This has been attributed to incomplete sample digestion. Here, we demonstrate that the combined effects of sample digestion, air filter impurities, and post-adsorption of the analytes contribute to the interference of the analysis. Particular attention should be paid to post-adsorption of analytes onto air filters after acid digestion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of sample digestion, air filter contamination, and post-adsorption on the analysis of trace elements in air particulate matter

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiao Jin [Department of Environment and Climate Change, Environmental Forensic and Analytical Science Section, New South Wales (Australia); Department of Applied Chemistry, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing (China); Wan, Pingyu [Department of Applied Chemistry, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing (China); Foley, Roy [Department of Environment and Climate Change, Environmental Forensic and Analytical Science Section, New South Wales (Australia)

2012-11-15

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma MS are the major analytical tools for trace elements in environmental matrices, however, the underestimate of certain trace elements in analysis of air particulate matter by these two techniques has long been observed. This has been attributed to incomplete sample digestion. Here, we demonstrate that the combined effects of sample digestion, air filter impurities, and post-adsorption of the analytes contribute to the interference of the analysis. Particular attention should be paid to post-adsorption of analytes onto air filters after acid digestion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

Science.gov (United States)

Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

2014-02-01

This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications. © 2013.

Permeability of gypsum samples dehydrated in air

Science.gov (United States)

Milsch, Harald; Priegnitz, Mike; Blöcher, Guido

2011-09-01

We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.

Air-side performance of a micro-channel heat exchanger in wet surface conditions

Directory of Open Access Journals (Sweden)

Srisomba Raviwat

2017-01-01

Full Text Available The effects of operating conditions on the air-side heat transfer, and pressure drop of a micro-channel heat exchanger under wet surface conditions were studied experimentally. The test section was an aluminum micro-channel heat exchanger, consisting of a multi-louvered fin and multi-port mini-channels. Experiments were conducted to study the effects of inlet relative humidity, air frontal velocity, air inlet temperature, and refrigerant temperature on air-side performance. The experimental data were analyzed using the mean enthalpy difference method. The test run was performed at relative air humidities ranging between 45% and 80%; air inlet temperature ranges of 27, 30, and 33°C; refrigerant-saturated temperatures ranging from 18 to 22°C; and Reynolds numbers between 128 and 166. The results show that the inlet relative humidity, air inlet temperature, and the refrigerant temperature had significant effects on heat transfer performance and air-side pressure drop. The heat transfer coefficient and pressure drop for the micro-channel heat exchanger under wet surface conditions are proposed in terms of the Colburn j factor and Fanning f factor.

Sampling procedure for lake or stream surface water chemistry

Science.gov (United States)

Robert Musselman

2012-01-01

Surface waters collected in the field for chemical analyses are easily contaminated. This research note presents a step-by-step detailed description of how to avoid sample contamination when field collecting, processing, and transporting surface water samples for laboratory analysis.

Air-spun PLA nanofibers modified with reductively sheddable hydrophilic surfaces for vascular tissue engineering: synthesis and surface modification.

Science.gov (United States)

Ko, Na Re; Sabbatier, Gad; Cunningham, Alexander; Laroche, Gaétan; Oh, Jung Kwon

2014-02-01

Polylactide (PLA) is a class of promising biomaterials that hold great promise for various biological and biomedical applications, particularly in the field of vascular tissue engineering where it can be used as a fibrous mesh to coat the inside of vascular prostheses. However, its hydrophobic surface providing nonspecific interactions and its limited ability to further modifications are challenges that need to be overcome. Here, the development of new air-spun PLA nanofibers modified with hydrophilic surfaces exhibiting reduction response is reported. Surface-initiated atom transfer radical polymerization allows for grafting pendant oligo(ethylene oxide)-containing polymethacrylate (POEOMA) from PLA air-spun fibers labeled with disulfide linkages. The resulting PLA-ss-POEOMA fibers exhibit enhanced thermal stability and improved surface properties, as well as thiol-responsive shedding of hydrophilic POEOMA by the cleavage of its disulfide linkages in response to reductive reactions, thus tuning the surface properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A newly developed grab sampling system for collecting stratospheric air over Antarctica

Directory of Open Access Journals (Sweden)

Hideyuki Honda

1996-07-01

Full Text Available In order to measure the concentrations of various minor constituents and their isotopic ratios in the stratosphere over Antarctica, a simple grab sampling system was newly developed. The sampling system was designed to be launched by a small number of personnel using a rubber balloon under severe experimental conditions. Special attention was paid to minimize the contamination of sample air, as well as to allow easy handling of the system. The sampler consisted mainly of a 15l sample container with electromagnetic and manual valves, control electronics for executing the air sampling procedures and sending the position and status information of the sampler to the ground station, batteries and a transmitter. All these parts were assembled in an aluminum frame gondola with a shock absorbing system for landing. The sampler was equipped with a turn-over mechanism of the gondola to minimize contamination from the gondola, as well as with a GPS receiver and a rawinsonde for its tracking. Total weight of the sampler was about 11kg. To receive, display and store the position and status data of the sampling system at the ground station, a simple data acquisition system with a portable receiver and a microcomputer was also developed. A new gas handling system was prepared to simplify the injection of He gas into the balloon. For air sampling experiments, three sampling systems were launched at Syowa Station (69°00′S, 39°35′E, Antarctica and then recovered on sea ice near the station on January 22 and 25,1996.

Temporal and spatial assessments of minimum air temperature using satellite surface temperature measurements in Massachusetts, USA.

Science.gov (United States)

Kloog, Itai; Chudnovsky, Alexandra; Koutrakis, Petros; Schwartz, Joel

2012-08-15

Although meteorological stations provide accurate air temperature observations, their spatial coverage is limited and thus often insufficient for epidemiological studies. Satellite data expand spatial coverage, enhancing our ability to estimate near surface air temperature (Ta). However, the derivation of Ta from surface temperature (Ts) measured by satellites is far from being straightforward. In this study, we present a novel approach that incorporates land use regression, meteorological variables and spatial smoothing to first calibrate between Ts and Ta on a daily basis and then predict Ta for days when satellite Ts data were not available. We applied mixed regression models with daily random slopes to calibrate Moderate Resolution Imaging Spectroradiometer (MODIS) Ts data with monitored Ta measurements for 2003. Then, we used a generalized additive mixed model with spatial smoothing to estimate Ta in days with missing Ts. Out-of-sample tenfold cross-validation was used to quantify the accuracy of our predictions. Our model performance was excellent for both days with available Ts and days without Ts observations (mean out-of-sample R(2)=0.946 and R(2)=0.941 respectively). Furthermore, based on the high quality predictions we investigated the spatial patterns of Ta within the study domain as they relate to urban vs. non-urban land uses. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of air polishing and an amino acid buffered hypochlorite solution to dentin surfaces and periodontal ligament cell survival, attachment, and spreading.

Science.gov (United States)

Schmidlin, Patrick R; Fujioka-Kobayashi, Masako; Mueller, Heinz-Dieter; Sculean, Anton; Lussi, Adrian; Miron, Richard J

2017-06-01

The aim of this study is to examine morphological changes of dentin surfaces following air polishing or amino acid buffered hypochlorite solution application and to assess their influence on periodontal ligament (PDL) cell survival, attachment, and spreading to dentin discs in vitro. Bovine dentin discs were treated with either (i) Classic, (ii) Plus, or (iii) Perio powder (EMS). Furthermore, Perisolv® a hypochlorite solution buffered with various amino acids was investigated. Untreated dentin discs served as controls. Morphological changes to dentin discs were assessed using scanning electron microscopy (SEM). Human PDL cells were seeded onto the respectively treated discs, and samples were then investigated for PDL cell survival, attachment, and spreading using a live/dead assay, adhesion assay, and SEM imaging, respectively. Both control and Perisolv®-rinsed dentin discs demonstrated smooth surfaces at low and high magnifications. The Classic powders demonstrated the thickest coating followed by the Powder Plus. The Perio powder demonstrated marked alterations of dentin discs by revealing the potential to open dentinal tubules even before rinsing. Seeding of PDL cells demonstrated an almost 100 % survival rate on all samples demonstrating very high biocompatibility for all materials. Significantly higher PDL cell numbers were observed on samples treated with the Perio powder and the Perisolv® solution (approximately 40 % more cells; p air polishing or application with Perisolv®. Future in vitro and animal testing is necessary to further characterize the beneficial effects of either system in a clinical setting. The use of air polishing or application with Perisolv amino acid buffered hypochlorite solution was effective in treating root surfaces and allowed for near 100 % PDL cell survival, attachment, and spreading onto all root surfaces.

Surface studies of plasma processed Nb samples

International Nuclear Information System (INIS)

Tyagi, Puneet V.; Doleans, Marc; Hannah, Brian S.; Afanador, Ralph; Stewart, Stephen; Mammosser, John; Howell, Matthew P; Saunders, Jeffrey W; Degraff, Brian D; Kim, Sang-Ho

2015-01-01

Contaminants present at top surface of superconducting radio frequency (SRF) cavities can act as field emitters and restrict the cavity accelerating gradient. A room temperature in-situ plasma processing technology for SRF cavities aiming to clean hydrocarbons from inner surface of cavities has been recently developed at the Spallation Neutron Source (SNS). Surface studies of the plasma-processed Nb samples by Secondary ion mass spectrometry (SIMS) and Scanning Kelvin Probe (SKP) showed that the NeO_2 plasma processing is very effective to remove carbonaceous contaminants from top surface and improves the surface work function by 0.5 to 1.0 eV.

Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

Science.gov (United States)

Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.;

Polytetrafluoroethylene surface modification by filamentary and homogeneous dielectric barrier discharges in air

International Nuclear Information System (INIS)

Fang Zhi; Hao Lili; Yang Hao; Xie Xiangqian; Qiu Yuchang; Edmund, Kuffel

2009-01-01

In this paper, polytetrafluoroethylene (PTFE) films are modified using non-equilibrium plasma generated by homogeneous DBD in air at medium pressure, and the results are compared to those treated by using filamentary DBD in air at atmospheric pressure. The surface properties of PTFE films before and after the treatments are studied using contact angle and surface energy measurement, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the plasma treatments modify the PTFE surface in both morphology and composition. The PTFE films modified in both treatments show a remarkable decrease in water contact and a remarkable increase in surface energy. XPS analysis reveals that oxygen-containing polar groups are introduced onto the PTFE surface, and SEM analysis shows that the surfaces of the films are etched after both the treatments. It is found that homogeneous DBD is more effective in PTFE surface modification than filamentary DBD as it can make the contact angle decline to a lower level by introducing more oxygen-containing groups, and the possible reason for this effect is discussed.

Dioxin emission factors for automobiles from tunnel air sampling in Northern Taiwan.

Science.gov (United States)

Chang, Moo Been; Chang, Shu Hao; Chen, Yuan Wu; Hsu, Hsuan Chien

2004-06-05

This study measured PCDD/F concentrations in tunnel air and vehicle exhaust. The ambient air samples were collected with air samplers (Tisch PS-1) complying with USEPA TO-9A. The results indicate that the tunnel air had a PCDD/F TEQ concentration about two times as high as that of outside air (47.3 and 57.1 fg-I-TEQ/m3 for tunnel air vs. 37.1 fg-I-TEQ/m3 and 23.3 fg-I-TEQ/m3 for outside air, respectively). This provides the direct evidence that PCDD/F compounds are emitted from the combustion processes in gasoline- and diesel-fueled engines. According to the tunnel study, the emission factors ranged from 5.83 to 59.2 pg I-TEQ/km for gasoline vehicles and 23.32 to 236.65 pg I-TEQ/km of diesel vehicles. This indicates that the dioxin emission factor in Taiwan is lower than that measured in USA, Norway and Germany. When the speed of the diesel vehicle was set at 40 km/h, the dioxin concentration emitted from diesel vehicle was 278 pg/m3 (6.27 pg-I-TEQ/m3) from tailpipe testing. However, when the diesel vehicle was idled, the dioxin concentration increased greatly to 4078 pg/m3 (41.9 pg-I-TEQ/m3). From the results of tunnel air sampling, the PCDD/Fs emission from automobiles in Taiwan was estimated as 3.69 g I-TEQ per year. Copryright 2003 Elsevier B.V.

Effects of Northern Hemisphere Sea Surface Temperature Changes on the Global Air Quality

Science.gov (United States)

Yi, K.; Liu, J.

2017-12-01

The roles of regional sea surface temperature (SST) variability on modulating the climate system and consequently the air quality are investigated using the Community Earth System Model (CESM). Idealized, spatially uniform SST anomalies of +/- 1 °C are superimposed onto the North Pacific, North Atlantic, and North Indian Oceans individually. Ignoring the response of natural emissions, our simulations suggest large seasonal and regional variability of surface O3 and PM2.5 concentrations in response to SST anomalies, especially during boreal summers. Increasing the SST by 1 °C in one of the oceans generally decreases the surface O3 concentrations from 1 to 5 ppbv while increases the anthropogenic PM2.5 concentrations from 0.5 to 3 µg m-3. We implement the integrated process rate (IPR) analysis in CESM and find that meteorological transport in response to SST changes is the key process causing air pollutant perturbations in most cases. During boreal summers, the increase in tropical SST over different ocean basins enhances deep convection, which significantly increases the air temperature over the upper troposphere and trigger large-scale subsidence over nearby and remote regions. These processes tend to increase tropospheric stability and suppress rainfall at lower mid-latitudes. Consequently, it reduces the vertical transport of O3 to the surface while facilitating the accumulation of PM2.5 concentrations over most regions. In addition, this regional SST warming may also considerably suppress intercontinental transport of air pollution as confirmed with idealized CO-like tracers. Our findings indicate a robust linkage between basin-scale SST variability and regional air quality, which can help local air quality management.

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

Science.gov (United States)

Ioannidou, A.; Vasileiadis, A.; Melas, D.

2012-04-01

The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62' N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Efficient maximal Poisson-disk sampling and remeshing on surfaces

KAUST Repository

Guo, Jianwei; Yan, Dongming; Jia, Xiaohong; Zhang, Xiaopeng

2015-01-01

Poisson-disk sampling is one of the fundamental research problems in computer graphics that has many applications. In this paper, we study the problem of maximal Poisson-disk sampling on mesh surfaces. We present a simple approach that generalizes the 2D maximal sampling framework to surfaces. The key observation is to use a subdivided mesh as the sampling domain for conflict checking and void detection. Our approach improves the state-of-the-art approach in efficiency, quality and the memory consumption.

Efficient maximal Poisson-disk sampling and remeshing on surfaces

KAUST Repository

Guo, Jianwei

2015-02-01

Poisson-disk sampling is one of the fundamental research problems in computer graphics that has many applications. In this paper, we study the problem of maximal Poisson-disk sampling on mesh surfaces. We present a simple approach that generalizes the 2D maximal sampling framework to surfaces. The key observation is to use a subdivided mesh as the sampling domain for conflict checking and void detection. Our approach improves the state-of-the-art approach in efficiency, quality and the memory consumption.

A Geostatistical Approach to Indoor Surface Sampling Strategies

DEFF Research Database (Denmark)

Schneider, Thomas; Petersen, Ole Holm; Nielsen, Allan Aasbjerg

1990-01-01

Particulate surface contamination is of concern in production industries such as food processing, aerospace, electronics and semiconductor manufacturing. There is also an increased awareness that surface contamination should be monitored in industrial hygiene surveys. A conceptual and theoretical...... framework for designing sampling strategies is thus developed. The distribution and spatial correlation of surface contamination can be characterized using concepts from geostatistical science, where spatial applications of statistics is most developed. The theory is summarized and particulate surface...... contamination, sampled from small areas on a table, have been used to illustrate the method. First, the spatial correlation is modelled and the parameters estimated from the data. Next, it is shown how the contamination at positions not measured can be estimated with kriging, a minimum mean square error method...

Holographic optical tweezers for object manipulations at an air-liquid surface.

Science.gov (United States)

Jesacher, Alexander; Fürhapter, Severin; Maurer, Christian; Bernet, Stefan; Ritsch-Marte, Monika

2006-06-26

We investigate holographic optical tweezers manipulating micro-beads at a suspended air-liquid interface. Axial confinement of the particles in the two-dimensional interface is maintained by the interplay between surface tension and gravity. Therefore, optical trapping of the micro-beads is possible even with a long distance air objective. Efficient micro-circulation of the liquid can be induced by fast rotating beads, driven by the orbital angular momentum transfer of incident Laguerre-Gaussian (doughnut) laser modes. Our setup allows various ways of creating a tailored dynamic flow of particles and liquid within the surface. We demonstrate examples of surface manipulations like efficient vortex pumps and mixers, interactive particle flow steering by arrays of vortex pumps, the feasibility of achieving a "clocked" traffic of micro beads, and size-selective guiding of beads along optical "conveyor belts".

Hydrogen and fluorine in the surfaces of lunar samples

International Nuclear Information System (INIS)

Leich, D.A.; Goldberg, R.H.; Burnett, D.S.; Tombrello, T.A.

1974-04-01

The resonant nuclear reaction F-19 (p, alpha gamma)O-16 was used to perform depth sensitive analyses for both fluorine and hydrogen in lunar samples. The resonance at 0.83 MeV (center-of-mass) in this reaction was applied to the measurement of the distribution of trapped solar protons in lunar samples to depths of about 1 / 2 micrometer. These results are interpreted in terms of terrestrial H 2 O surface contamination and a redistribution of the implanted solar H which has been influenced by heavy radiation damage in the surface region. Results are also presented for an experiment to test the penetration of H 2 O into laboratory glass samples which have been irradiated with O-16 to simulate the radiation damaged surfaces of lunar glasses. Fluorine determinations were performed in a 1 pm surface layer on lunar samples using the same F-19(alpha gamma)O-16 resonance. The data are discussed from the standpoint of lunar fluorine and Teflon contamination. (U.S.)

Surface kinetics for catalytic combustion of hydrogen-air mixtures on platinum at atmospheric pressure in stagnation flows

Science.gov (United States)

Ikeda, H.; Sato, J.; Williams, F. A.

1995-03-01

Experimental studies of the combustion of premixed hydrogen-air mixtures impinging on the surface of a heated platinum plate at normal atmospheric pressure were performed and employed to draw inferences concerning surface reaction mechanisms and rate parameters applicable under practical conditions of catalytic combustion. Plate and gas temperatures were measured by thermocouples, and concentration profiles of major stable species in the gas were measured by gas-chromatographic analyses of samples withdrawn by quartz probes. In addition, ignition and extinction phenomena were recorded and interpreted with the aid of a heat balance at the surface and a previous flow-field analysis of the stagnation-point boundary layer. From the experimental and theoretical results, conclusions were drawn concerning the surface chemical-kinetic mechanisms and values of the elementary rate parameters that are consistent with the observations. In particular, the activation energy for the surface oxidation step H + OH → H 2O is found to be appreciably less at these high surface coverages than in the low-coverage limit.

Meso-scale wrinkled coatings to improve heat transfers of surfaces facing ambient air

International Nuclear Information System (INIS)

Kakiuchida, Hiroshi; Tajiri, Koji; Tazawa, Masato; Yoshimura, Kazuki; Shimono, Kazuaki; Nakagawa, Yukio; Takahashi, Kazuhiro; Fujita, Keisuke; Myoko, Masumi

2015-01-01

Meso-scale (micrometer-to submillimeter-scale) wrinkled surfaces coated on steel sheets used in outdoor storage and transport facilities for industrial low-temperature liquids were discovered to efficiently increase convective heat transfer between ambient air and the surface. The radiative and convective heat transfer coefficients of various wrinkled surfaces, which were formed by coating steel sheets with several types of shrinkable paints, were examined. The convective heat transfer coefficient of a surface colder than ambient air monotonically changed with average height difference and interval distance of the wrinkle undulation, where the proportions were 0.0254 and 0.0054 W/m 2 /K/μm, respectively. With this wrinkled coating, users can lower the possibility of condensation and reduce rust and maintenance cost of facilities for industrial low-temperature liquids. From the point of view of manufacturers, this coating method can be easily adapted to conventional manufacturing processes. - Highlights: • Various wrinkled surfaces were fabricated by a practical process. • Topographical effect on convection was parameterized separately from radiation. • Meso-scale wrinkled coatings increased convective heat transfer with ambient air. • Maintenance cost of outdoor steel sheets due to condensation can be reduced

Lessons learned from surface wipe sampling for lead in three workplaces.

Science.gov (United States)

Beaucham, Catherine; Ceballos, Diana; King, Bradley

2017-08-01

Surface wipe sampling in the occupational environment is a technique widely used by industrial hygienists. Although several organizations have promulgated standards for sampling lead and other metals, uncertainty still exists when trying to determine an appropriate wipe sampling strategy and how to interpret sampling results. Investigators from the National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluation Program have used surface wipe sampling as part of their exposure assessment sampling strategies in a wide range of workplaces. This article discusses wipe sampling for measuring lead on surfaces in three facilities: (1) a battery recycling facility; (2) a firing range and gun store; and (3) an electronic scrap recycling facility. We summarize our findings from the facilities and what we learned by integrating wipe sampling into our sampling plan. Wiping sampling demonstrated lead in non-production surfaces in all three workplaces and that the potential that employees were taking lead home to their families existed. We also found that the presence of metals such as tin can interfere with the colorimetric results. We also discuss the advantages and disadvantages of colorimetric analysis of surface wipe samples and the challenges we faced when interpreting wipe sampling results.

Air sampling in the workplace to meet the new part 20 requirements

International Nuclear Information System (INIS)

McGuire, S.; Hickey, E.E.; Knox, W.

1991-01-01

The US Nuclear Regulatory Commission is developing a Regulatory Guide on air sampling in the workplace to meet the requirements of the revised Part 20. The guide will be accompanied by a technical manual describing and giving examples of how to meet the recommendations in the guide. Draft versions of the guide and manual are scheduled to be published for public comment this year. A final guide and manual, revised to consider the public comments, are scheduled to be published in 1992. This talk will summarize some of the more important features of the guide and manual. In particular, the talk will discuss how to demonstrate that samples taken to estimate worker intakes are representative of the air inhaled by workers and what measurements are necessary if a licensee wants to adjust derived air concentrations to account for particle size

Experimental test of a novel multi-surface trough solar concentrator for air heating

International Nuclear Information System (INIS)

Zheng Hongfei; Tao Tao; Ma Ming; Kang Huifang; Su Yuehong

2012-01-01

Highlights: ► We made a prototype novel multi-surface trough solar concentrator for air heating. ► Circular and rectangular types of receiver were chosen for air heating in the test. ► The changes of instantaneous system efficiency with different air flow were obtained. ► The system has the advantage of high collection temperature, which can be over 140 °C. ► The average efficiency can exceed 45% at the outlet temperature of above 60 °C. - Abstract: This study presents the experimental test of a novel multi-surface trough solar concentrator for air heating. Three receivers of different air flow channels are individually combined with the solar concentrator. The air outlet temperature and solar irradiance were recorded for different air flow rates under the real weather condition and used to determine the collection efficiency and time constant of the air heater system. The characteristics of the solar air heater with different airflow channels are compared, and the variation of the daily efficiency with the normalized temperature change is also presented. The testing results indicates that the highest temperature of the air heater with a circular glass receiver can be over 140 °C. When the collection temperature is around 60 °C, the collection efficiency can be over 45%. For the rectangular receivers, the system also has a considerable daily efficiency at a larger air flow rate. The air heater based on the novel trough solar concentrator would be suitable for space heating and drying applications.

Comparison of air samples, nasal swabs, ear-skin swabs and environmental dust samples for detection of Methicillin Resistant Staphylococcus aureus (MRSA) in pig herds

DEFF Research Database (Denmark)

Agersø, Yvonne; Vigre, Håkan; Cavaco, Lina

2014-01-01

To identify a cost-effective and practical method for detection of methicillin-resistant Staphylococcus aureus (MRSA) in pig herds, the relative sensitivity of four sample types: nasal swabs, ear-skin (skin behind the ears) swabs, environmental dust swabs and air was compared. Moreover, dependency......-herd prevalence ⩾25%]. The results indicate that taking swabs of skin behind the ears (ten pools of five) was even more sensitive than taking nasal swabs (ten pools of five) at the herd level and detected significantly more positive samples. spa types t011, t034 and t4208 were observed. In conclusion, MRSA...... detection by air sampling is easy to perform, reduces costs and analytical time compared to existing methods, and is recommended for initial testing of herds. Ear-skin swab sampling may be more sensitive for MRSA detection than air sampling or nasal swab sampling....

Clean Air Act Guidelines and Standards for Solvent Use and Surface Coating Industry

Science.gov (United States)

This page contains the stationary sources of air pollution for the solvent use and surface coating industries, and their corresponding air pollution regulations. To learn more about the regulations for each industry, just click on the links below.

Air and Ground Surface Temperature Relations in a Mountainous Basin, Wolf Creek, Yukon Territory

Science.gov (United States)

Roadhouse, Emily A.

The links between climate and permafrost are well known, but the precise nature of the relationship between air and ground temperatures remains poorly understood, particularly in complex mountain environments. Although previous studies indicate that elevation and potential incoming solar radiation (PISR) are the two leading factors contributing to the existence of permafrost at a given location, additional factors may also contribute significantly to the existence of mountain permafrost, including vegetation cover, snow accumulation and the degree to which individual mountain landscapes are prone to air temperature inversions. Current mountain permafrost models consider only elevation and aspect, and have not been able to deal with inversion effects in a systematic fashion. This thesis explores the relationship between air and ground surface temperatures and the presence of surface-based inversions at 27 sites within the Wolf Creek basin and surrounding area between 2001 and 2006, as a first step in developing an improved permafrost distribution TTOP model. The TTOP model describes the relationship between the mean annual air temperature and the temperature at the top of permafrost in terms of the surface and thermal offsets (Smith and Riseborough, 2002). Key components of this model are n-factors which relate air and ground climate by establishing the ratio between air and surface freezing (winter) and thawing (summer) degree-days, thus summarizing the surface energy balance on a seasonal basis. Here we examine (1) surface offsets and (2) freezing and thawing n-factor variability at a number of sites through altitudinal treeline in the southern Yukon. Thawing n-factors (nt) measured at individual sites remained relatively constant from one year to the next and may be related to land cover. During the winter, the insulating effect of a thick snow cover results in higher surface temperatures, while thin snow cover results in low surface temperatures more closely

Sampling strategies for the analysis of reactive low-molecular weight compounds in air

NARCIS (Netherlands)

Henneken, H.

2006-01-01

Within this thesis, new sampling and analysis strategies for the determination of airborne workplace contaminants have been developed. Special focus has been directed towards the development of air sampling methods that involve diffusive sampling. In an introductory overview, the current

Satellite skill in detecting extreme episodes in near-surface air quality

Science.gov (United States)

Ruiz, D. J.; Prather, M. J.

2017-12-01

Ozone (O3) contributes to ambient air pollution, adversely affecting public health, agriculture, and ecosystems. Reliable, long-term, densely distributed surface networks are required to establish the scale, intensity and repeatability of major pollution events (designated here in a climatological sense as air quality extremes, AQX as defined in Schnell's work). Regrettably, such networks are only available for North America (NA) and Europe (EU), which does not include many populated regions where the deaths associated with air pollution exposure are alarmingly high. Directly measuring surface pollutants from space without lidar is extremely difficult. Mapping of daily pollution events requires cross-track nadir scanners and these have limited sensitivity to surface O3 levels. This work examines several years of coincident surface and OMI satellite measurements over NA-EU, in combination with a chemistry-transport model (CTM) hindcast of that period to understand how the large-scale AQX episodes may extend into the free troposphere and thus be more amenable to satellite mapping. We show how extreme NA-EU episodes are measured from OMI and then look for such patterns over other polluted regions of the globe. We gather individual high-quality O3 surface site measurements from these other regions, to check on our satellite detection. Our approach with global satellite detection would avoid issues associated with regional variations in seasonality, chemical regime, data product biases; and it does not require defining a separate absolute threshold for each data product (surface site and satellite). This also enables coherent linking of the extreme events into large-scale pollution episodes whose magnitude evolves over 100's of km for several days. Tools used here include the UC Irvine CTM, which shows that much of the O3 surface variability is lost at heights above 2 km, but AQX local events are readily seen in a 0-3 km column average. The OMI data are taken from X

Technical assessment of compliance with workplace air sampling requirements in the 300 Area

International Nuclear Information System (INIS)

Olsen, P.A.

1995-01-01

The purpose of this Technical Work Document is to satisfy HSRCM-1, the ''Hanford Site Radiological Control Manual.'' Article 551.4 of that manual states a requirement for a documented study of facility workplace air sampling programs (WPAS). This first revision of the original Supporting Document covers the period from January 1, 1995 to December 31, 1995. HSRCM-1 is the primary guidance for radiological control at Westinghouse Hanford Company (WHC). It was written to implement DOE/EH-0256T ''US Department of Energy Radiological Control Manual'' as it applies to programs at Hanford. As such, it complies with Title 10, Part 835 of the Code of Federal Regulations. There are also several Department of Energy (DOE) Orders, national consensus standards, and reports that provide criteria, standards, and requirements for workplace air sampling programs. This document provides a summary of these, as they apply to WHC facility workplace air sampling programs. This document also provides an evaluation of the compliance of 300 Areas' workplace air sampling program to the criteria, standards, and requirements and documents compliance with the requirements where appropriate. Where necessary, it also indicates changes needed to bring specific locations into compliance. The areas evaluated were the 340 Facility, the Advanced Reactor Operations Division Facilities, the N Reactor Fuels Supply Facility, and The Geotechnical Engineering Laboratory

Mineralization of bacterial cell mass on a photocatalytic surface in air

International Nuclear Information System (INIS)

Jacoby, W.A.; Maness, P.C.; Wolfrum, E.J.; Blake, D.M.; Fennell, J.A.

1998-01-01

Whole cells deposited on a titanium dioxide-coated surface have been oxidized in air to carbon dioxide via photocatalysis. This paper provides the first evidence that the organic matter in whole cells can be completely oxidized. Three experimental techniques were employed to monitor this reaction: scanning electron microscopy, 14 C radioisotope labeling experiments establish that the carbon content of E. coli is oxidized to form carbon dioxide with substantial closure of the mass balance. The batch reactor experiments corroborate the mass balance and provide a preliminary indication of the rate of the oxidation reaction. These results provide evidence that a photocatalytic surface used for disinfection can also be self-cleaning in an air-solid system

Climate Prediction Center (CPC) Global Land Surface Air Temperature Analysis

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A station observation-based global land monthly mean surface air temperature dataset at 0.5 0.5 latitude-longitude resolution for the period from 1948 to the present...

Climate Prediction Center (CPC) Global Land Surface Air Temperature Analysis

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A station observation-based global land monthly mean surface air temperature dataset at 0.5 x 0.5 latitude-longitude resolution for the period from 1948 to the...

Rapid surface sampling and archival record system (RSSAR)

International Nuclear Information System (INIS)

Barren, E.; Bracco, A.; Dorn, S.B.

1997-01-01

Purpose is to develop a rapid surface (concrete, steel) contamination measurement system that will provide a ''quick-look'' indication of contamination areas, an archival record, and an automated analysis. A bulk sampling oven is also being developed. The sampling device consists of a sampling head, a quick look detector, and an archiving system (sorbent tube). The head thermally desorbs semi-volatiles, such as PCBs, oils, etc., from concrete and steel surfaces; the volatilized materials are passed through a quick-look detector. Sensitivity of the detector can be attenuated for various contaminant levels. Volatilized materials are trapped in a tube filled with adsorbent. The tubes are housed in a magazine which also archives information about sampling conditions. Analysis of the tubes can be done at a later date. The concrete sampling head is fitted with a tungsten-halogen lamp; in laboratory experiments it has extracted model contaminants by heating the top 4mm of the surface to 250 C within 100-200 s. The steel sampling head has been tested on different types of steels and has extracted model contaminants within 30 s. A mathematical model of heat and mass transport in concrete has been developed. Rate of contaminant removal is at maximum when the moisture content is about 100 kg/m 3 . The system will be useful during decontamination and decommissioning operations

Evaluation of an ambient air sampling system for tritium (as tritiated water vapor) using silica gel adsorbent columns

International Nuclear Information System (INIS)

Patton, G.W.; Cooper, A.T.; Tinker, M.R.

1995-08-01

Ambient air samples for tritium analysis (as the tritiated water vapor [HTO] content of atmospheric moisture) are collected for the Hanford Site Surface Environmental Surveillance Project (SESP) using the solid adsorbent silica gel. The silica gel has a moisture sensitive indicator which allows for visual observation of moisture movement through a column. Despite using an established method, some silica gel columns showed a complete change in the color indicator for summertime samples suggesting that breakthrough had occurred; thus a series of tests was conducted on the sampling system in an environmental chamber. The purpose of this study was to determine the maximum practical sampling volume and overall collection efficiency for water vapor collected on silica gel columns. Another purpose was to demonstrate the use of an impinger-based system to load water vapor onto silica gel columns to provide realistic analytical spikes and blanks for the Hanford Site SESP. Breakthrough volumes (V b ) were measured and the chromatographic efficiency (expressed as the number of theoretical plates [N]) was calculated for a range of environmental conditions. Tests involved visual observations of the change in the silica gel's color indicator as a moist air stream was drawn through the column, measurement of the amount of a tritium tracer retained and then recovered from the silica gel, and gravimetric analysis for silica gel columns exposed in the environmental chamber

Technical assessment of workplace air sampling requirements at tank farm facilities. Revision 1

International Nuclear Information System (INIS)

Olsen, P.A.

1994-01-01

WHC-CM-1-6 is the primary guidance for radiological control at Westinghouse Hanford Company (WHC). It was written to implement DOE N 5480.6 ''US Department of Energy Radiological Control Manual'' as it applies to programs at Hanford which are now overseen by WHC. As such, it complies with Title 10, Part 835 of the Code of Federal Regulations. In addition to WHC-CM-1-6, there is HSRCM-1, the ''Hanford Site Radiological Control Manual'' and several Department of Energy (DOE) Orders, national consensus standards, and reports that provide criteria, standards, and requirements for workplace air sampling programs. This document provides a summary of these, as they apply to WHC facility workplace air sampling programs. This document also provides an evaluation of the compliance of Tank Farms' workplace air sampling program to the criteria, standards, and requirements and documents compliance with the requirements where appropriate. Where necessary, it also indicates changes needed to bring specific locations into compliance

Technical assessment of TRUSAF for compliance with work place air sampling. Revision 1

International Nuclear Information System (INIS)

Butler, J.D.

1995-01-01

The purpose of this Technical Work Document is to satisfy WHC-CM-1-6, the ''WHC Radiological Control Manual.'' This first revision of the original Supporting Document covers the period from January 1, 1994 to December 31, 1994. WHC-CM-1-6 is the primary guidance for radiological control at Westinghouse Hanford Company (WHC). As such, it complies with Title 10, Part 835 of the Code of Federal Regulations. In addition to WHC-CM-1-6, there is HSRCM-1, the ''Hanford Site Radiological Control Manual'' and several Department of Energy (DOE) Orders, national consensus standards, and reports that provide criteria, standards, and requirements for workplace air sampling programs. This document provides a summary of these, as they apply to WHC facility workplace air sampling programs. this document also provides an evaluation of the compliance of the TRUSAF workplace air sampling program to the criteria, standards, and requirements and documents. Where necessary, it also indicates changes needed to bring specific locations into compliance

Responses of Surface Ozone Air Quality to Anthropogenic Nitrogen Deposition

Science.gov (United States)

Zhang, L.; Zhao, Y.; Tai, A. P. K.; Chen, Y.; Pan, Y.

2017-12-01

Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. We combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by addition of atmospheric deposited nitrogen: emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index (LAI) in the model), could increase surface ozone from increased biogenic VOC emissions, but could also decrease ozone due to higher ozone dry deposition velocities. Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations show general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, Western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate and land use driven surface ozone changes at regional scales, and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere-atmosphere interactions, which can have important

Spatially-varying surface roughness and ground-level air quality in an operational dispersion model

International Nuclear Information System (INIS)

Barnes, M.J.; Brade, T.K.; MacKenzie, A.R.; Whyatt, J.D.; Carruthers, D.J.; Stocker, J.; Cai, X.; Hewitt, C.N.

2014-01-01

Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. -- Highlights: • Spatially variable roughness improved performance of an operational model. • Scenario modelling explored effect of reduced roughness on air pollution. • Reducing surface roughness can increase modelled ground-level pollution. • Damped vertical mixing outweighs increased horizontal advection in model study. • Result should hold for any model with a land-surface coupling based on roughness. -- Spatially varying roughness improves model simulations of urban air pollutant dispersion. Reducing roughness does not always decrease ground-level pollution concentrations

Simple and rapid measurement of α-rays on smear samples using air luminescence

International Nuclear Information System (INIS)

Takiue, M.

1980-01-01

The α-activity collected on smear samples has been measured indirectly using an air luminescence counting method and a liquid scintillation spectrometer. In this method, air luminescence, attributed to the fluorescence emitted by nitrogen molecules excited by α-rays in air, serves to detect α-rays. Thus, sample preparation and α-ray measurement are simple and rapid, and moreover, no radioactive waste solution is produced. Taking into account a low background and a counting efficiency between 10 and 20%, it is estimated that the detectable limit for α-ray measurement is about 1 x 10 -7 μCi/cm 2 for loose contamination. This method is convenient to use in the routine analysis of α-ray-emitting nuclides on smear paper. (author)

AFM fluid delivery/liquid extraction surface sampling/electrostatic spray cantilever probe

Science.gov (United States)

Van Berkel, Gary J.

2015-06-23

An electrospray system comprises a liquid extraction surface sampling probe. The probe comprises a probe body having a liquid inlet and a liquid outlet, and having a liquid extraction tip. A solvent delivery conduit is provided for receiving solvent liquid from the liquid inlet and delivering the solvent liquid to the liquid extraction tip. An open liquid extraction channel extends across an exterior surface of the probe body from the liquid extraction tip to the liquid outlet. An electrospray emitter tip is in liquid communication with the liquid outlet of the liquid extraction surface sampling probe. A system for analyzing samples, a liquid junction surface sampling system, and a method of analyzing samples are also disclosed.

Elemental analysis of air particulate samples in Jakarta area by x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Yumiarti; Yusuf, M.; Mellawati, June; Menry, Yulizon; Surtipanti S

1998-01-01

Determination of elements in air particulate samples collected from Jakarta, especially from industrial area Pulo Gadung, also from residence, office, and recreation sites had been carried out. The samples collected periodically from August through December 1996. The elements were analyzed by X-ray fluorescence spectrometry method. Quantitative and qualitative analyses were done using QXAS AXIL (Quantitative X-ray Analysis System of x-ray Spectra by Iterative Least squares fitting) and QAES (Quantitative Analyses of Environmental Samples) package program. Results of the analyses showed that the content of heavy metal elements in air particulate samples from all areas studied were still below the maximum permissible concentration. (authors)

Sampling technologies and air pollution control devices for gaseous and particulate arsenic: a review

International Nuclear Information System (INIS)

Helsen, Lieve

2005-01-01

Direct measurement of arsenic release requires a good sampling and analysis procedure in order to capture and detect the total amount of metals emitted. The literature is extensively reviewed in order to evaluate the efficiency of full field-scale and laboratory scale techniques for capturing particulate and gaseous emissions of arsenic from the thermo-chemical treatment of different sources of arsenic. Furthermore, trace arsenic concentrations in ambient air, national standard sampling methods and arsenic analysis methods are considered. Besides sampling techniques, the use of sorbents is also reviewed with respect to both approaches (1) to prevent the metals from exiting with the flue gas and (2) to react or combine with the metals in order to be collected in air pollution control systems. The most important conclusion is that submicron arsenic fumes are difficult to control in conventional air pollution control devices. Complete capture of the arsenic species requires a combination of particle control and vapour control devices. - Submicron arsenic fumes are difficult to control in conventional air pollution control devices

chemical and microbiological assessment of surface water samples

African Journals Online (AJOL)

PROF EKWUEME

were investigated in this study: Nine samples from different surface water bodies, two samples from two effluent sources ... Ezeagu, Udi, Nkanu, Oji River and some parts of Awgu and Aninri ..... Study of Stream Output from Small Catchments.

Design of modified annulus air sampling system for the detection of leakage in waste transfer line

International Nuclear Information System (INIS)

Deokar, U.V; Khot, A.R.; Mathew, P.; Ganesh, G.; Tripathi, R.M.; Srivastava, Srishti

2018-01-01

Various liquid waste streams are generated during the operation of reprocessing plant. The High Level (HL), Intermediate Level (IL) and Low Level (LL) liquid wastes generated, are transferred from reprocessing plant to Waste Management Facility. These respective waste streams are transferred through pipe-in-pipe lines along the shielded concrete trench. For detection of radioactive leakage from primary waste transfer line into secondary line, sampling of the annulus air between the two pipes is carried out. The currently installed pressurized annulus air sampling system did not have online leakage detection provision. Hence, there are chances of personal exposure and airborne activity in the working area. To overcome these design flaws, free air flow modified online annulus air sampling system with more safety features is designed

Technical assessment of compliance with work place air sampling requirements at T Plant. Revision No. 1

International Nuclear Information System (INIS)

Hackworth, M.F.

1995-01-01

The US DOE requires its contractors to conduct air sampling to detect and evaluate airborne radioactive material in the workplace. Hanford Reservation T Plant compliance with workplace air sampling requirements has been assessed. Requirements, basis for determining compliance and recommendations are included

Removal of PCB from indoor air and surface materials by introduction of additional sorbing materials

DEFF Research Database (Denmark)

Gunnarsen, Lars Bo; Lyng, Nadja; Kolarik, Barbara

2017-01-01

Alleviation of indoor PCB contamination is extremely expensive because PCB from old primary sources has redistributed to most other surfaces over time. This study investigates the introduction of new removable sorbing materials as a method instantly lowering the concentration of PCB in indoor air...... and slowly decontaminating old surface materials. In three bedrooms of a contaminated apartment respectively new painted gypsum boards, sheets of flexible polyurethane foam and activated carbon fabric were introduced. The PCB concentrations in room air were monitored before the intervention and several times...... during the following 10 months. The PCB concentrations in the old surface materials as well as the new materials were also measured. An immediate reduction of PCB concentration in indoor air, a gradual increase of PCB in new material and as well a gradual reduction in old surface materials were...

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

Directory of Open Access Journals (Sweden)

Melas D.

2012-04-01

Full Text Available The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62′ N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p < 0.0001, and also between 7Be concentration and the temperature T (°C (R = 0.97, p < 0.001, confirm that the increased rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Rapid surface sampling and archival record system

Energy Technology Data Exchange (ETDEWEB)

Barren, E.; Penney, C.M.; Sheldon, R.B. [GE Corporate Research and Development Center, Schenectady, NY (United States)] [and others

1995-10-01

A number of contamination sites exist in this country where the area and volume of material to be remediated is very large, approaching or exceeding 10{sup 6} m{sup 2} and 10{sup 6} m{sup 3}. Typically, only a small fraction of this material is actually contaminated. In such cases there is a strong economic motivation to test the material with a sufficient density of measurements to identify which portions are uncontaminated, so extensively they be left in place or be disposed of as uncontaminated waste. Unfortunately, since contamination often varies rapidly from position to position, this procedure can involve upwards of one million measurements per site. The situation is complicated further in many cases by the difficulties of sampling porous surfaces, such as concrete. This report describes a method for sampling concretes in which an immediate distinction can be made between contaminated and uncontaminated surfaces. Sample acquisition and analysis will be automated.

Air Entrainment and Surface Ripples in a Turbulent Ship Hull Boundary Layer

Science.gov (United States)

Masnadi, Naeem; Erinin, Martin; Duncan, James H.

2017-11-01

The air entrainment and free-surface fluctuations caused by the interaction of a free surface and the turbulent boundary layer of a vertical surface-piercing plate is studied experimentally. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes. This belt device is mounted inside a large water tank with the water level set just below the top edge of the belt. The belt, rollers, and supporting frame are contained within a sheet metal box to keep the device dry except for one 6-meter-long straight test section. The belt is accelerated suddenly from rest until reaching constant speed in order to create a temporally evolving boundary layer analogous to the spatially evolving boundary layer that would exist along a surface-piercing towed flat plate. Surface ripples are measured using a cinematic laser-induced fluorescence technique with the laser sheet oriented parallel or normal to the belt surface. Air entrainment events and bubble motions are recorded from underneath the water surface using a stereo imaging system. Measurements of small bubbles, that tend to stay submerged for a longer time, are planned via a high-speed digital in-line holographic system. The support of the Office of Naval Research is gratefully acknowledged.

A climatology of 7Be in surface air in European Union

International Nuclear Information System (INIS)

Hernández-Ceballos, M.A.; Cinelli, G.; Marín Ferrer, M.; Tollefsen, T.; De Felice, L.; Nweke, E.; Tognoli, P.V.; Vanzo, S.; De Cort, M.

2015-01-01

This study presents a European-wide analysis of the spatial and temporal distribution of the cosmogenic isotope 7 Be in surface air. This is the first time that a long term database of 34 sampling sites that regularly provide data to the Radioactivity Environmental Monitoring (REM) network, managed by the Joint Research Centre (JRC) in Ispra, is used. While temporal coverage varies between stations, some of them have delivered data more or less continuously from 1984 to 2011. The station locations were considerably heterogeneous, both in terms of latitude and altitude, a range which should ensure a high degree of representativeness of the results. The mean values of 7 Be activity concentration presented a spatial distribution value ranging from 2.0 to 5.4 mBq/m 3 over the European Union. The results of the ANOVA analysis of all 7 Be data available indicated that its temporal and spatial distributions were mainly explained by the location and characteristic of the sampling sites rather than its temporal distribution (yearly, seasonal and monthly). Higher 7 Be concentrations were registered at the middle, compared to high-latitude, regions. However, there was no correlation with altitude, since all stations are sited within the atmospheric boundary layer. In addition, the total and yearly analyses of the data indicated a dynamic range of 7 Be activity for each solar cycle and phase (maximum or minimum), different impact on stations having been observed according to their location. Finally, the results indicated a significant seasonal and monthly variation for 7 Be activity concentration across the European Union, with maximum concentrations occurring in the summer and minimum in the winter, although with differences in the values reached. The knowledge of the horizontal and vertical distribution of this natural radionuclide in the atmosphere is a key parameter for modelling studies of atmospheric processes, which are important phenomena to be taken into account in

Decadal-scale teleconnection between South Atlantic SST and southeast Australia surface air temperature in austral summer

Science.gov (United States)

Xue, Jiaqing; Li, Jianping; Sun, Cheng; Zhao, Sen; Mao, Jiangyu; Dong, Di; Li, Yanjie; Feng, Juan

2018-04-01

Austral summer (December-February) surface air temperature over southeast Australia (SEA) is found to be remotely influenced by sea surface temperature (SST) in the South Atlantic at decadal time scales. In austral summer, warm SST anomalies in the southwest South Atlantic induce concurrent above-normal surface air temperature over SEA. This decadal-scale teleconnection occurs through the eastward propagating South Atlantic-Australia (SAA) wave train triggered by SST anomalies in the southwest South Atlantic. The excitation of the SAA wave train is verified by forcing experiments based on both linear barotropic and baroclinic models, propagation pathway and spatial scale of the observed SAA wave train are further explained by the Rossby wave ray tracing analysis in non-uniform basic flow. The SAA wave train forced by southwest South Atlantic warming is characterized by an anomalous anticyclone off the eastern coast of the Australia. Temperature diagnostic analyses based on the thermodynamic equation suggest anomalous northerly flows on western flank of this anticyclone can induce low-level warm advection anomaly over SEA, which thus lead to the warming of surface air temperature there. Finally, SST-forced atmospheric general circulation model ensemble experiments also demonstrate that SST forcing in the South Atlantic is associated with the SAA teleconnection wave train in austral summer, this wave train then modulate surface air temperature over SEA on decadal timescales. Hence, observations combined with numerical simulations consistently demonstrate the decadal-scale teleconnection between South Atlantic SST and summertime surface air temperature over SEA.

An intrinsic algorithm for parallel Poisson disk sampling on arbitrary surfaces.

Science.gov (United States)

Ying, Xiang; Xin, Shi-Qing; Sun, Qian; He, Ying

2013-09-01

Poisson disk sampling has excellent spatial and spectral properties, and plays an important role in a variety of visual computing. Although many promising algorithms have been proposed for multidimensional sampling in euclidean space, very few studies have been reported with regard to the problem of generating Poisson disks on surfaces due to the complicated nature of the surface. This paper presents an intrinsic algorithm for parallel Poisson disk sampling on arbitrary surfaces. In sharp contrast to the conventional parallel approaches, our method neither partitions the given surface into small patches nor uses any spatial data structure to maintain the voids in the sampling domain. Instead, our approach assigns each sample candidate a random and unique priority that is unbiased with regard to the distribution. Hence, multiple threads can process the candidates simultaneously and resolve conflicts by checking the given priority values. Our algorithm guarantees that the generated Poisson disks are uniformly and randomly distributed without bias. It is worth noting that our method is intrinsic and independent of the embedding space. This intrinsic feature allows us to generate Poisson disk patterns on arbitrary surfaces in IR(n). To our knowledge, this is the first intrinsic, parallel, and accurate algorithm for surface Poisson disk sampling. Furthermore, by manipulating the spatially varying density function, we can obtain adaptive sampling easily.

2017 Annual Terrestrial Sampling Plan for Sandia National Laboratories/New Mexico on Kirtland Air Force Base

Energy Technology Data Exchange (ETDEWEB)

Griffith, Stacy R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-02-01

The 2017 Annual Terrestrial Sampling Plan for Sandia National Laboratories/New Mexico on Kirtland Air Force Base has been prepared in accordance with the “Letter of Agreement Between Department of Energy, National Nuclear Security Administration, Sandia Field Office (DOE/NNSA/SFO) and 377th Air Base Wing (ABW), Kirtland Air Force Base (KAFB) for Terrestrial Sampling” (signed January 2017), Sandia National Laboratories, New Mexico (SNL/NM). The Letter of Agreement requires submittal of an annual terrestrial sampling plan.

2018 Annual Terrestrial Sampling Plan for Sandia National Laboratories/New Mexico on Kirtland Air Force Base.

Energy Technology Data Exchange (ETDEWEB)

Griffith, Stacy R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2018-01-01

The 2018 Annual Terrestrial Sampling Plan for Sandia National Laboratories/New Mexico on Kirtland Air Force Base has been prepared in accordance with the “Letter of Agreement Between Department of Energy, National Nuclear Security Administration, Sandia Field Office (DOE/NNSA/SFO) and 377th Air Base Wing (ABW), Kirtland Air Force Base (KAFB) for Terrestrial Sampling” (signed January 2017), Sandia National Laboratories, New Mexico (SNL/NM). The Letter of Agreement requires submittal of an annual terrestrial sampling plan.

Gas-chromatographic quantitative determination of argon in air samples, by elimination of oxigen

International Nuclear Information System (INIS)

Sofronie, E.

1982-08-01

A method of gas-chromatographic quantitative determination of argon in air samples, by elimination of oxygen, is presented. Experiments were carried out in a static system. Conditions for the application of the method in dynamic systems are specified. Sensibility of the method: 5 10 -4 cm 3 Ar per cm 3 of air. (author)

Environmental surveillance master sampling schedule

Energy Technology Data Exchange (ETDEWEB)

Bisping, L.E.

1993-01-01

Environmental surveillance of the Hanford Site and surrounding areas is conducted by the Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE). Samples are routinely collected and analyzed to determine the quality of air, surface water, ground water, soil, sediment, wildlife, vegetation, foodstuffs, and farm products at Hanford Site and surrounding communities. This document contains the planned schedule for routine sample collection for the Surface Environmental Surveillance Project (SESP) and Drinking Water Project, and Ground-Water Surveillance Project.

Surface sampling concentration and reaction probe

Science.gov (United States)

Van Berkel, Gary J; Elnaggar, Mariam S

2013-07-16

A method of analyzing a chemical composition of a specimen is described. The method can include providing a probe comprising an outer capillary tube and an inner capillary tube disposed co-axially within the outer capillary tube, where the inner and outer capillary tubes define a solvent capillary and a sampling capillary in fluid communication with one another at a distal end of the probe; contacting a target site on a surface of a specimen with a solvent in fluid communication with the probe; maintaining a plug volume proximate a solvent-specimen interface, wherein the plug volume is in fluid communication with the probe; draining plug sampling fluid from the plug volume through the sampling capillary; and analyzing a chemical composition of the plug sampling fluid with an analytical instrument. A system for performing the method is also described.

Early Detection of Foot-And-Mouth Disease Virus from Infected Cattle Using A Dry Filter Air Sampling System.

Science.gov (United States)

Pacheco, J M; Brito, B; Hartwig, E; Smoliga, G R; Perez, A; Arzt, J; Rodriguez, L L

2017-04-01

Foot-and-mouth disease (FMD) is a highly contagious livestock disease of high economic impact. Early detection of FMD virus (FMDV) is fundamental for rapid outbreak control. Air sampling collection has been demonstrated as a useful technique for detection of FMDV RNA in infected animals, related to the aerogenous nature of the virus. In the current study, air from rooms housing individual (n = 17) or two groups (n = 4) of cattle experimentally infected with FDMV A24 Cruzeiro of different virulence levels was sampled to assess the feasibility of applying air sampling as a non-invasive, screening tool to identify sources of FMDV infection. Detection of FMDV RNA in air was compared with first detection of clinical signs and FMDV RNA levels in serum and oral fluid. FMDV RNA was detected in room air samples 1-3 days prior (seven animals) or on the same day (four animals) as the appearance of clinical signs in 11 of 12 individually housed cattle. Only in one case clinical signs preceded detection in air samples by one day. Overall, viral RNA in oral fluid or serum preceded detection in air samples by 1-2 days. Six individually housed animals inoculated with attenuated strains did not show clinical signs, but virus was detected in air in one of these cases 3 days prior to first detection in oral fluid. In groups of four cattle housed together, air detection always preceded appearance of clinical signs by 1-2 days and coincided more often with viral shedding in oral fluid than virus in blood. These data confirm that air sampling is an effective non-invasive screening method for detecting FMDV infection in confined to enclosed spaces (e.g. auction barns, milking parlours). This technology could be a useful tool as part of a surveillance strategy during FMD prevention, control or eradication efforts. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Ambient air sampling for radioactive air contaminants at Los Alamos National Laboratory: A large research and development facility

International Nuclear Information System (INIS)

Eberhart, C.F.

1998-01-01

This paper describes the ambient air sampling program for collection, analysis, and reporting of radioactive air contaminants in and around Los Alamos National Laboratory (LANL). Particulate matter and water vapor are sampled continuously at more than 50 sites. These samples are collected every two weeks and then analyzed for tritium, and gross alpha, gross beta, and gamma ray radiation. The alpha, beta, and gamma measurements are used to detect unexpected radionuclide releases. Quarterly composites are analyzed for isotopes of uranium ( 234 U, 235 U, 238 U), plutonium ( 238 Pu, 239/249 Pu), and americium ( 241 Am). All of the data is stored in a relational database with hard copies as the official records. Data used to determine environmental concentrations are validated and verified before being used in any calculations. This evaluation demonstrates that the sampling and analysis process can detect tritium, uranium, plutonium, and americium at levels much less than one percent of the public dose limit of 10 millirems. The isotopic results also indicate that, except for tritium, off-site concentrations of radionuclides potentially released from LANL are similar to typical background measurements

Chemosorption sampling and analysis of formaldehyde in air. Influence on recovery during the simultaneous sampling of formaldehyde, phenol, furfural and furfuryl alcohol

Energy Technology Data Exchange (ETDEWEB)

Andersson, K.; Hallgren, C.; Levin, J.O.; Nilsson, C.A.

1981-12-01

A method based on trapping formaldehyde on a 2,4-dinitrodinitrophenylhydrazine-coated porous polymer (Amberlite XAD-2) was evaluated for air sampling in occupational environments. The aldehyde is converted to its 2,4-dinitrophenylhydrazone on the adsorbent. The influence of some organic compounds which often occur together with formaldehyde-furfural, phenol and furfuryl alcohol--was studied. The results show that the method allows the sampling of formaldehyde in the range 0.01--1.0 mg/m3 of air, based on a 3-1 (15 min) sample and a coating of 1%. Furfural, phenol, and furfuryl alcohol do not interfere and may be conveniently sampled at the same time. Formaldehyde and furfural hydrazones were analyzed by high-performance liquid chromatography, phenol and furfuryl alcohol by gas chromatography.

High efficiency mixed species radioiodine air sampling, readout, and dose assessment system

International Nuclear Information System (INIS)

Distenfeld, C.; Klemish, J.

1976-05-01

Reactor accidents require monitoring to assess the impact to persons in the environment. This implies methods and apparatus to accurately and economically sample and evaluate possible released activity. The development of a prototype iodine air sampling system that can differentiate against noble gas activity and be evaluated by standard Civil Defense instrumentation is reported. The apparatus can efficiently (95 percent) collect organic or inorganic, particulate or gaseous radioiodine in concentrations below stable atmospheric iodine, and under severe ambient conditions. Response to noble fission gases was reduced to less than 4 x 10 -4 of an equal iodine airborne activity by heating the collector to approximately 100 0 C. Reliable sample size, +-5 percent, was achieved by using a simple air flow regulator. Thyroid dose commitment was mathematically and graphically related to the iodine isotope distribution expected in the environment and to the response of the Civil Defense CDV-700 instrument used to evaluate the sample. Sensitivity of the method allows dose assessment of 1 to 2 rads to a child's thyroid

Time-resolved imaging of a compressible air disc under a drop impacting on a solid surface

KAUST Repository

Li, Erqiang

2015-09-07

When a drop impacts on a solid surface, its rapid deceleration is cushioned by a thin layer of air, which leads to the entrapment of a bubble under its centre. For large impact velocities the lubrication pressure in this air layer becomes large enough to compress the air. Herein we use high-speed interferometry, with 200 ns time-resolution, to directly observe the thickness evolution of the air layer during the entire bubble entrapment process. The initial disc radius and thickness shows excellent agreement with available theoretical models, based on adiabatic compression. For the largest impact velocities the air is compressed by as much as a factor of 14. Immediately following the contact, the air disc shows rapid vertical expansion. The radial speed of the surface minima just before contact, can reach 50 times the impact velocity of the drop.

The intraseasonal variability of winter semester surface air temperature in Antarctica

Directory of Open Access Journals (Sweden)

Lejiang Yu

2011-02-01

Full Text Available This study investigates systematically the intraseasonal variability of surface air temperature over Antarctica by applying empirical orthogonal function (EOF analysis to the National Centers for Environmental Prediction, US Department of Energy, Reanalysis 2 data set for the period of 1979 through 2007. The results reveal the existence of two major intraseasonal oscillations of surface temperature with periods of 26–30 days and 14 days during the Antarctic winter season in the region south of 60°S. The first EOF mode shows a nearly uniform spatial pattern in Antarctica and the Southern Ocean associated with the Antarctic Oscillation. The mode-1 intraseasonal variability of the surface temperature leads that of upper atmosphere by one day with the largest correlation at 300-hPa level geopotential heights. The intraseasonal variability of the mode-1 EOF is closely related to the variations of surface net longwave radiation the total cloud cover over Antarctica. The other major EOF modes reveal the existence of eastward propagating phases over the Southern Ocean and marginal region in Antarctica. The leading two propagating modes respond to Pacific–South American modes. Meridional winds induced by the wave train from the tropics have a direct influence on the surface air temperature over the Southern Ocean and the marginal region of the Antarctic continent.

Radiological air monitoring and sample analysis research and development progress report

International Nuclear Information System (INIS)

1992-01-01

Sponsored by a Department Of Energy (DOE) research and development grant, the State of Idaho INEL Oversight Program (OP) personnel designed an independent air monitoring system that provides detection of the presence of priority airborne contaminants potentially migrating beyond INEL boundaries. Initial locations for off-site ambient air monitoring stations were chosen in consultation with: DOE and NOAA reports; Mesodif modeling; review of the relevant literature; and communication with private contractors and experts in pertinent fields. Idaho State University (ISU) has initiated an Environmental Monitoring Program (EMP). The EMP provides an independent monitoring function as well as a training ground for students. Students learn research techniques dedicated to environmental studies and learn analytical skills and rules of compliance related to monitoring. ISU-EMP assisted OP in specific aspects of identifying optimum permanent monitoring station locations, and in selecting appropriate sample collection equipment for each station. The authorization to establish, prepare and install sampling devices on selected sites was obtained by OP personnel in conjunction with ISU-EMP personnel. All samples described in this program are collected by OP or ISU-EMP personnel and returned to the ISU for analysis. This report represents the summary of results of those samples collected and analyzed for radioactivity during the year of 1992

Evaluation of entrance surface air kerma in pediatric chest radiography

International Nuclear Information System (INIS)

Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J.L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

2014-01-01

The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior–posterior (AP) and posterior–anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0–1 y, 1–5 y, 5–10 y, and 10–15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels. - Highlights: • The entrance surface air kerma of chest X-ray examinations in pediatric patients was estimated. • The data were analyzed for patients aged up to 15 y, stratified by age. • The doses of LAT examinations were 40% higher than of AP/PA because of kV used. • An increase in kV with a decrease in mAs leads to significant dose reduction

The sampling of sulfur dioxide in air with impregnated filter paper

NARCIS (Netherlands)

Huygen, C.

1963-01-01

A method is suggested for the sampling of sulfur dioxide in air with impregnated filter paper instead of bubblers. The best aqueous impregnating solution contained potassium hydroxide with glycerol or triethanolamine. The possibilities and limitations of the method are discussed. High collection

The secondary electron yield of air exposed metal surfaces at the example of niobium

CERN Document Server

Scheuerlein, C; Taborelli, M

2002-01-01

The secondary electron yield (SEY) variation of atomically clean metal surfaces due to air exposures and during subsequent heat treatments is described with the example of a sputter-deposited Nb thin film. Corresponding variations of the surface chemical composition have been monitored using AES and SSIMS. On the basis of these results and of previously obtained SEY results on metals and metal oxides the origin of the SEY variations is discussed. The SEY increase, which is generally observed during long lasting air exposures of clean metals, is mainly caused by the adsorption of an airborne carbonaceous contamination layer. The estimated value of about 3 for the maximum SEY of this layer is higher than that of all pure metals. Only in some cases the air-formed oxide can contribute to the air exposure induced SEY increase while many oxides have a lower SEY than their parent metals. From the experimental data it can also be excluded that the SEY increase during air exposures is mainly due to an increased second...

Capacity constrained blue-noise sampling on surfaces

KAUST Repository

Zhang, Sen; Guo, Jianwei; Zhang, Hui; Jia, Xiaohong; Yan, Dongming; Yong, Junhai; Wonka, Peter

2015-01-01

regularizer of the Centroidal Voronoi Tessellation (CVT) energy, our approach enforces an exact capacity constraint using the restricted power tessellation on surfaces. Our approach is a generalization of the previous 2D blue noise sampling technique using

Surface Resistance Measurements of LHC Dipole Beam Screen Samples

CERN Document Server

Caspers, Friedhelm; Ruggiero, F; Tan, J; Tsutsui, H

2000-01-01

An estimate of the resistive losses in the LHC dipole beam screen is given from cold surface resistance measurements using the shielded pair technique. Several beam screen samples have been evaluated, with different copper coating methods, including a sample with ribbed surface envisaged to reduce electron cloud losses thanks to its low reflectivity. Experimental data, derived by a proper analysis of the measured Q-factors and including error estimates are compared with theoretical predictions of the anomalous skin effect.

Classification of Surface and Deep Soil Samples Using Linear Discriminant Analysis

International Nuclear Information System (INIS)

Wasim, M.; Ali, M.; Daud, M.

2015-01-01

A statistical analysis was made of the activity concentrations measured in surface and deep soil samples for natural and anthropogenic gamma-emitting radionuclides. Soil samples were obtained from 48 different locations in Gilgit, Pakistan covering about 50 km/sup 2/ areas at an average altitude of 1550 m above sea level. From each location two samples were collected: one from the top soil (2-6 cm) and another from a depth of 6-10 cm. Four radionuclides including /sup 226/Ra, /sup 232/Th, /sup 40/K and /sup 137/Cs were quantified. The data was analyzed using t-test to find out activity concentration difference between the surface and depth samples. At the surface, the median activity concentrations were 23.7, 29.1, 4.6 and 115 Bq kg/sup -1/ for 226Ra, 232Th, 137Cs and 40K respectively. For the same radionuclides, the activity concentrations were respectively 25.5, 26.2, 2.9 and 191 Bq kg/sup -1/ for the depth samples. Principal component analysis (PCA) was applied to explore patterns within the data. A positive significant correlation was observed between the radionuclides /sup 226/Ra and /sup 232/Th. The data from PCA was further utilized in linear discriminant analysis (LDA) for the classification of surface and depth samples. LDA classified surface and depth samples with good predictability. (author)

Surface-Air Mercury Fluxes Across Western North America: A Synthesis of Spatial Trends and Controlling Variables.

Science.gov (United States)

Eckley, C.; Tate, M.; Lin, C. J.; Gustin, M. S.; Dent, S.; Eagles-Smith, C.; Lutz, M.; Wickland, K.; Wang, B.; Gray, J.; Edwards, G. C.; Krabbenhoft, D. P.; Smith, D. B.

2016-12-01

Mercury (Hg) emission and deposition can occur to and from soils and are an important component of the global atmospheric Hg budget. This presentation focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere.

Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

Science.gov (United States)

Eckley, Chris S.; Tate, Michael T.; Lin, Che-Jen; Gustin, Mae S.; Dent, Stephen; Eagles-Smith, Collin A.; Lutz, Michelle A; Wickland, Kimberly; Wang, Bronwen; Gray, John E.; Edwards, Grant; Krabbenhoft, David P.; Smith, David

2016-01-01

Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere.

Performance characteristics of solar air heater with surface mounted obstacles

International Nuclear Information System (INIS)

Bekele, Adisu; Mishra, Manish; Dutta, Sushanta

2014-01-01

Highlights: • Solar air heater with delta shaped obstacles have been studied. • Obstacle angle of incidence strongly affects the thermo-hydraulic performance. • Thermal performance of obstacle mounted collectors is superior to smooth collectors. • Thermo-hydraulic performance of the present SAH is higher than those in previous studies. - Abstract: The performance of conventional solar air heaters (SAHs) can be improved by providing obstacles on the heated wall (i.e. on the absorber plate). Experiments have been performed to collect heat transfer and flow-friction data from an air heater duct with delta-shaped obstacles mounted on the absorber surface and having an aspect ratio 6:1 resembling the conditions close to the solar air heaters. This study encompassed for the range of Reynolds number (Re) from 2100 to 30,000, relative obstacle height (e/H) from 0.25 to 0.75, relative obstacle longitudinal pitch (P l /e) from 3/2 to 11/2, relative obstacle transverse pitch (P t /b) from 1 to 7/3 and the angle of incidence (α) varied from 30° to 90°. The thermo-hydraulic performance characteristics of SAH have been compared with the previous published works and the optimum range of the geometries have been explored for the better performance of such air-heaters compared to the other designs of solar air heaters

Airborne detection and quantification of swine influenza a virus in air samples collected inside, outside and downwind from swine barns.

Directory of Open Access Journals (Sweden)

Cesar A Corzo

Full Text Available Airborne transmission of influenza A virus (IAV in swine is speculated to be an important route of virus dissemination, but data are scarce. This study attempted to detect and quantify airborne IAV by virus isolation and RRT-PCR in air samples collected under field conditions. This was accomplished by collecting air samples from four acutely infected pig farms and locating air samplers inside the barns, at the external exhaust fans and downwind from the farms at distances up to 2.1 km. IAV was detected in air samples collected in 3 out of 4 farms included in the study. Isolation of IAV was possible from air samples collected inside the barn at two of the farms and in one farm from the exhausted air. Between 13% and 100% of samples collected inside the barns tested RRT-PCR positive with an average viral load of 3.20E+05 IAV RNA copies/m³ of air. Percentage of exhaust positive air samples also ranged between 13% and 100% with an average viral load of 1.79E+04 RNA copies/m³ of air. Influenza virus RNA was detected in air samples collected between 1.5 and 2.1 Km away from the farms with viral levels significantly lower at 4.65E+03 RNA copies/m³. H1N1, H1N2 and H3N2 subtypes were detected in the air samples and the hemagglutinin gene sequences identified in the swine samples matched those in aerosols providing evidence that the viruses detected in the aerosols originated from the pigs in the farms under study. Overall our results indicate that pigs can be a source of IAV infectious aerosols and that these aerosols can be exhausted from pig barns and be transported downwind. The results from this study provide evidence of the risk of aerosol transmission in pigs under field conditions.

Studies on radioactivities of dust samples in the air at high altitudes

International Nuclear Information System (INIS)

Kohara, Eri; Muronoi, Naohiro

2015-01-01

The radioactivity concentrations of airborne dust samples were studied. The samples had been collected at high altitude by the Japan Air Self-Defense Force from April 2013 to March 2014. The obtained data were used for gross beta radioactivity analysis and gamma nuclide analysis. It is shown that cesium 137 was mainly detected at the 10 km and 3 km altitude of central area of Japan in several samples. Gaseous radioiodine was not detected in all the samples. Radioactive xenon was detected but the concentration did not show significant difference to the background level. (author)

Microbes at Surface-Air Interfaces: The Metabolic Harnessing of Relative Humidity, Surface Hygroscopicity, and Oligotrophy for Resilience

Science.gov (United States)

Stone, Wendy; Kroukamp, Otini; Korber, Darren R.; McKelvie, Jennifer; Wolfaardt, Gideon M.

2016-01-01

The human environment is predominantly not aqueous, and microbes are ubiquitous at the surface-air interfaces with which we interact. Yet microbial studies at surface-air interfaces are largely survival-oriented, whilst microbial metabolism has overwhelmingly been investigated from the perspective of liquid saturation. This study explored microbial survival and metabolism under desiccation, particularly the influence of relative humidity (RH), surface hygroscopicity, and nutrient availability on the interchange between these two phenomena. The combination of a hygroscopic matrix (i.e., clay or 4,000 MW polyethylene glycol) and high RH resulted in persistent measurable microbial metabolism during desiccation. In contrast, no microbial metabolism was detected at (a) hygroscopic interfaces at low RH, and (b) less hygroscopic interfaces (i.e., sand and plastic/glass) at high or low RH. Cell survival was conversely inhibited at high RH and promoted at low RH, irrespective of surface hygroscopicity. Based on this demonstration of metabolic persistence and survival inhibition at high RH, it was proposed that biofilm metabolic rates might inversely influence whole-biofilm resilience, with ‘resilience’ defined in this study as a biofilm’s capacity to recover from desiccation. The concept of whole-biofilm resilience being promoted by oligotrophy was supported in desiccation-tolerant Arthrobacter spp. biofilms, but not in desiccation-sensitive Pseudomonas aeruginosa biofilms. The ability of microbes to interact with surfaces to harness water vapor during desiccation was demonstrated, and potentially to harness oligotrophy (the most ubiquitous natural condition facing microbes) for adaptation to desiccation. PMID:27746774

Composition of Surface Adsorbed Layer of TiO2 Stored in Ambient Air

Directory of Open Access Journals (Sweden)

Zakharenko V.S.

2017-11-01

Full Text Available The processes of dark, UV, and visible light promoted desorption of surface species were investigated for three different TiO2 samples: TiO2 prepared by dispersion of the titania single crystal, TiO2 prepared by combustion of a pyrotechnic mixture in air, and commercial TiO2 P25. The composition of the adsorbed layer was identified in the dark and under UV and visible light irradiation. The composition of desorption products showed the dependence of the adsorption layer state on the TiO2 nature. Methane photodesorption was detected only for the commercial TiO2 P25. Possible reasons for methane emission include the capturing of complete molecules during the TiO2 production process and photocatalytic hydrogenation of CO2 under UV-light.

Early air sampling in Higashi-Hiroshima after the Fukushima Daiichi Nuclear Power Plant accident and subsequent sampling in Minami-Souma City from October 2011 to September 2012

International Nuclear Information System (INIS)

Shizuma, Kiyoshi; Kajimoto, Tsuyoshi; Endo, Satoru

2013-01-01

Soon after the accident that occurred at the Fukushima Daiichi Nuclear Power Plant on March 11, 2011, air sampling was performed in Higashi-Hiroshima (about 800 km from Fukushima). The sampling began on March 20, and a high-volume air sampler was used. The first radionuclide observed was "1"3"1I (on March 30), and "1"3"7Cs, "1"3"4Cs, "1"3"6Cs, and "1"3"2Te were observed thereafter. According to the sampling, the maximum concentration in the air occurred on April 7 and again on April 18. After April 30, no radionuclides released due to the accident were observed. Since "1"3"7Cs and "1"3"4Cs have a long half-life (30 and 2 y, respectively), all of the air filters were measured again in February through March of 2012 using a well-type Ge detector. The results of these measurements showed that "1"3"7Cs was already observed on March 21. Later on, air sampling was performed at Minami-Souma City, Fukushima (October 2011 to September 2012). The purpose of this sampling was to investigate whether any radionuclides were released from the forest and flew up into the air from the ground, or were carried by the wind in winter or via pollen in spring. Results showed that the radioactive concentration was quite low and no seasonal variation occurred, indicating that no radionuclides flew up into the air from the ground, nor were any released from the forest via wind or pollen. (author)

Transport Powder and Liquid Samples by Surface Acoustic Waves

Science.gov (United States)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar

2009-01-01

Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed to move in opposite directions. In the preliminary tests, a speed of 180 mm/s was achieved for powder transportation. The detailed experimental setup and results are presented in this paper. The transporting mechanism can potentially be applied to miniaturize sample analysis system or " lab-on-chip" devices.

Application of the CaF2(Eu) scintillator to 85Kr monitoring in atmospheric air samples

International Nuclear Information System (INIS)

Wilhelmova, Ludmila; Dvorak, Zdenek; Tomasek, Milan; Stukheil, Karel

1986-01-01

A detection system with a CaF 2 (Eu) scintillator has been developed for monitoring β-radiation of 85 Kr in atmospheric air samples. The geometry of the detector chamber was optimized to achieve maximum detection efficiency. The design of the detector is described and values of the detection efficiency are presented for various compositions and pressures of the gaseous samples. The conditions for calibration of the detector used for monitoring of 85 Kr in enriched air samples have been established. (author)

Actinide nuclides in environmental air and precipitation samples after the Chernobyl accident

International Nuclear Information System (INIS)

Rosner, G.; Hoetzl, H.; Winkler, R.

1988-01-01

The present paper describes the analysis of isotopes of uranium, neptunium, plutonium, americium and curium, in air and deposition samples taken at our laboratory site 10 km north of Munich, subsequent to the Chernobyl accident. Uranium-234, 237 U, 238 U, 239 Np, 238 Pu, 239+240 Pu and 242 Cm have been identified and upper limits of detection have been established for 241 Am and 244 Cm. Deposition and air concentration values are discussed. 12 refs., 1 fig., 2 tabs

Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

Science.gov (United States)

Wang, K.; Li, Y.; Wang, X.; Yuan, M.

2013-12-01

Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

Hydroxyl radical reactivity at the air-ice interface

Directory of Open Access Journals (Sweden)

T. F. Kahan

2010-01-01

Full Text Available Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at air-ice interfaces, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH anthracene at air-water interfaces, but no loss was observed at air-ice interfaces. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL that exists at air-ice interfaces.

The determination of plutonium isotopes in environmental samples

International Nuclear Information System (INIS)

Siripirom, Lopchai.

1983-01-01

The concentration of plutonium in environmental samples such as soil, water, and surface air in the middle part of Thailand were studied. The surface air were collected only at the fifth floor of the Office of Atomic Energy for Peace (OAEP). Plutonium-242 was used as a tracer. Soil and air samples were dissolved by pyrosulphate fusion, and plutonium was co-precipitated with barium sulfate. Then dissolved the precipitate in perchloric acid. Plutonium was extracted out by using solvent bis-(2-ethylhexyl) phosphoric acid (HDEHP). Plutonium in water samples were coprecipitated with iron (III) hydroxide and were dissolved in 8 M. nitric acid. Then the plutonium was separated out by using anion exchange resin, Dowex 1x4. After the solvent extraction or the anion exchange, plutonium was coprecipitated with cerous hydroxide. The activities of plutonium were measured by a surface barrier detector for about 24 hours. Lower limit of detection for 1,440 minutes is 0.012 pCi. These studies showed that only plutonium-239, 240 was observed. The range of activities of plutonium-239, 240 in soil were 0.002-0.157 pCi/g (dry), in water were 0.1-81 f Ci/l, and in air were 7-330 a Ci/m 3 . However, the plutonium concentrations in these studies are far below the maximum permissible concentration (MPC) recommended by International Commission on Radiological Protection (ICRP) for general population which is equal to 3x10 8 f Ci/l of water and 5x10 6 a Ci/m 3 of air

Radiation damage of paper samples in in-air PIXE analysis

International Nuclear Information System (INIS)

Matsuyama, S.; Endo, H.; Ishii, K.; Yamazaki, H.; Tokai, Y.; Sugimoto, A.; Yamamoto, K.; Satoh, T.; Orihara, H.

1999-01-01

Degradation of paper caused by beam irradiation was investigated from a viewpoint of discoloration in PIXE analysis and its application to the paper samples of archaeology. Two types of paper (Japanese paper and fine quality paper) were tested in in-air PIXE analysis with 3 MeV protons. The degree of discoloration was quantitatively measured by the use of a colorimeter. The degree of discoloration was different for each tested paper and corresponded to the radiation dose of ions. It is resulted that even the in-air PIXE analysis should be carefully applied to archaeological treasures. Because discoloration of all tested paper decreased gradually at first but then increased after a few weeks. However, this phenomenon can be used to develop a technique of funny coloration. (author)

Radiation damage of paper samples in in-air PIXE analysis

Energy Technology Data Exchange (ETDEWEB)

Matsuyama, S.; Endo, H.; Ishii, K.; Yamazaki, H.; Tokai, Y.; Sugimoto, A.; Yamamoto, K.; Satoh, T. [Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Miyagi (Japan); Orihara, H. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

1999-07-01

Degradation of paper caused by beam irradiation was investigated from a viewpoint of discoloration in PIXE analysis and its application to the paper samples of archaeology. Two types of paper (Japanese paper and fine quality paper) were tested in in-air PIXE analysis with 3 MeV protons. The degree of discoloration was quantitatively measured by the use of a colorimeter. The degree of discoloration was different for each tested paper and corresponded to the radiation dose of ions. It is resulted that even the in-air PIXE analysis should be carefully applied to archaeological treasures. Because discoloration of all tested paper decreased gradually at first but then increased after a few weeks. However, this phenomenon can be used to develop a technique of funny coloration. (author)

Effects of platinum stagnation surface on the lean extinction limits of premixed methane/air flames at moderate surface temperatures

Energy Technology Data Exchange (ETDEWEB)

Wiswall, J.T.; Li, J.; Wooldridge, M.S.; Im, H.G. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States)

2011-01-15

A stagnation flow reactor was used to study the effects of platinum on the lean flammability limits of atmospheric pressure premixed methane/air flames at moderate stagnation surface temperatures. Experimental and computational methods were used to quantify the equivalence ratio at the lean extinction limit ({phi}{sub ext}) and the corresponding stagnation surface temperature (T{sub s}). A range of flow rates (57-90 cm/s) and corresponding strain rates were considered. The results indicate that the gas-phase methane/air flames are sufficiently strong relative to the heterogeneous chemistry for T{sub s} conditions less than 750 K that the platinum does not affect {phi}{sub ext}. The computational results are in good agreement with the experimentally observed trends and further indicate that higher reactant flow rates (>139 cm/s) and levels of dilution (>{proportional_to}10% N{sub 2}) are required to weaken the gas-phase flame sufficiently for surface reaction to play a positive role on extending the lean flammability limits. (author)

Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

Energy Technology Data Exchange (ETDEWEB)

Mamede, Anne-Sophie, E-mail: anne-sophie.mamede@ensc-lille.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Nuns, Nicolas, E-mail: nicolas.nuns@univ-lille1.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Cristol, Anne-Lise, E-mail: anne-lise.cristol@ec-lille.fr [University Lille, CNRS, Centrale Lille, Arts et Métiers Paris Tech, FRE 3723 – LML – Laboratoire de Mécanique de Lille, F-59000 Lille (France); Cantrel, Laurent, E-mail: laurent.cantrel@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); Souvi, Sidi, E-mail: sidi.souvi@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); and others

2016-04-30

Graphical abstract: - Highlights: • Mutitechnique characterisation of oxidised 304L. • Oxidation at high temperature under steam and air conditions of 304L stainless steel. • Chromium and manganese oxides formed in the outer layer. • Oxide profiles differ in air or steam atmosphere. - Abstract: In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8–12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe{sub 2}O{sub 3} oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

Energy Technology Data Exchange (ETDEWEB)

Eckley, Chris S., E-mail: eckley.chris@epa.gov [US Environmental Protection Agency, Region-10, Seattle, WA 98101 (United States); Tate, Mike T. [US Geological Survey, Middleton, WI 53562 (United States); Lin, Che-Jen [Center for Advances on Water and Air quality, Lamar University, Beaumont, TX 77710 (United States); Gustin, Mae [Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV 89557 (United States); Dent, Stephen [CDM Smith, Portland, OR 97205 (United States); Eagles-Smith, Collin [US Geological Survey, Corvallis, OR 97331 (United States); Lutz, Michelle A. [US Geological Survey, Middleton, WI 53562 (United States); Wickland, Kimberly P. [US Geological Survey Boulder, CO 80303 (United States); Wang, Bronwen [US Geological Survey, Anchorage, AK 99508 (United States); Gray, John E. [US Geological Survey, Denver, CO 80225 (United States); Edwards, Grant C. [Department of Environment and Geography, Macquarie University, North Ryde, NSW 2109 (Australia); Krabbenhoft, Dave P. [US Geological Survey, Middleton, WI 53562 (United States); Smith, David B. [US Geological Survey, Denver, CO 80225 (United States)

2016-10-15

Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere. - Highlights: • Soil-air Hg fluxes are an important component of the

Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables

International Nuclear Information System (INIS)

Eckley, Chris S.; Tate, Mike T.; Lin, Che-Jen; Gustin, Mae; Dent, Stephen; Eagles-Smith, Collin; Lutz, Michelle A.; Wickland, Kimberly P.; Wang, Bronwen; Gray, John E.; Edwards, Grant C.; Krabbenhoft, Dave P.; Smith, David B.

2016-01-01

Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis projects. A database of existing Hg flux data collected using the dynamic flux chamber (DFC) approach from almost a thousand locations was created for the Western North America region. Statistical analysis was performed on the data to identify the important variables controlling Hg fluxes and to allow spatiotemporal scaling. The results indicated that most of the variability in soil-air Hg fluxes could be explained by variations in soil-Hg concentrations, solar radiation, and soil moisture. This analysis also identified that variations in DFC methodological approaches were detectable among the field studies, with the chamber material and sampling flushing flow rate influencing the magnitude of calculated emissions. The spatiotemporal scaling of soil-air Hg fluxes identified that the largest emissions occurred from irrigated agricultural landscapes in California. Vegetation was shown to have a large impact on surface-air Hg fluxes due to both a reduction in solar radiation reaching the soil as well as from direct uptake of Hg in foliage. Despite high soil Hg emissions from some forested and other heavily vegetated regions, the net ecosystem flux (soil flux + vegetation uptake) was low. Conversely, sparsely vegetated regions showed larger net ecosystem emissions, which were similar in magnitude to atmospheric Hg deposition (except for the Mediterranean California region where soil emissions were higher). The net ecosystem flux results highlight the important role of landscape characteristics in effecting the balance between Hg sequestration and (re-)emission to the atmosphere. - Highlights: • Soil-air Hg fluxes are an important component of the

Influence of the convective surface transfer coefficients on the Heat, Air, and Moisture (HAM) building performance

DEFF Research Database (Denmark)

Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten

2009-01-01

Current models to predict heat, air and moisture (HAM) conditions in buildings assume constant boundary conditions for the temperature and relative humidity of the neighbouring air and for the surface heat and moisture transfer coefficients. These assumptions may introduce errors in the predicted...... influence on the predicted hygrothermal conditions at the surface of a building component and on the heat and vapour exchange with the indoor environment....

Sampling methods for recovery of human enteric viruses from environmental surfaces.

Science.gov (United States)

Turnage, Nicole L; Gibson, Kristen E

2017-10-01

Acute gastroenteritis causes the second highest infectious disease burden worldwide. Human enteric viruses have been identified as leading causative agents of acute gastroenteritis as well as foodborne illnesses in the U.S. and are generally transmitted by fecal-oral contamination. There is growing evidence of transmission occurring via contaminated fomite including food contact surfaces. Additionally, human enteric viruses have been shown to remain infectious on fomites over prolonged periods of time. To better understand viral persistence, there is a need for more studies to investigate this phenomenon. Therefore, optimization of surface sampling methods is essential to aid in understanding environmental contamination to ensure proper preventative measures are being applied. In general, surface sampling studies are limited and highly variable among recovery efficiencies and research parameters used (e.g., virus type/density, surface type, elution buffers, tools). This review aims to discuss the various factors impacting surface sampling of viruses from fomites and to explore how researchers could move towards a more sensitive and standard sampling method. Copyright © 2017 Elsevier B.V. All rights reserved.

CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767

NARCIS (Netherlands)

Assonov, S.S.; Brenninkmeijer, C.A.M.; Koeppel, C.; Röckmann, T.

2009-01-01

Analytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft-based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and

Detachment of polystyrene particles from collector surfaces by surface tension forces induced by air-bubble passage through a parallel plate flow chamber

NARCIS (Netherlands)

Wit, PJ; vanderMei, HC; Busscher, HJ

1997-01-01

By allowing an air-bubble to pass through a parallel plate flow chamber with negatively charged, colloidal polystyrene particles adhering to the bottom collector plate of the chamber, the detachment of adhering particles stimulated by surface tension forces induced by the passage of a liquid-air

Measurement of the Tracer Gradient and Sampling System Bias of the Hot Fuel Examination Facility Stack Air Monitoring System

Energy Technology Data Exchange (ETDEWEB)

Glissmeyer, John A.; Flaherty, Julia E.

2011-07-20

This report describes tracer gas uniformity and bias measurements made in the exhaust air discharge of the Hot Fuel Examination Facility at Idaho National Laboratory. The measurements were a follow-up on earlier measurements which indicated a lack of mixing of the two ventilation streams being discharged via a common stack. The lack of mixing is detrimental to the accuracy of air emission measurements. The lack of mixing was confirmed in these new measurements. The air sampling probe was found to be out of alignment and that was corrected. The suspected sampling bias in the air sample stream was disproved.

Contamination of the air and other environmental samples of the Ulm region by radioactive fission products after the accident of the Chernobyl reactor

International Nuclear Information System (INIS)

Krivan, V.; Egger, K.P.; Hausbeck, R.; Schmid, W.

1986-01-01

Since April 30, 1986, the radioactivity of the fission products released by the accident of the Chernobyl reactor has been measured in the air of the city of Ulm. The airborne dust samples were collected with flow calibrated samplers on cellulose acetate membrane filters and counted with a high resolution gamma ray spectrometer. Later on, the radioactivity measurements were expanded to other relevant environmental samples contaminated by radioactive atmospheric precipitates including grass, spruce needles, mosses, lichens, various kinds of food, drinking water, asphalt and concrete surface layers, municipal sewage sludge and sewage sludge ash. This paper reports the obtained results. (orig.) [de

Retrieval of sea surface air temperature from satellite data over Indian Ocean: An empirical approach

Digital Repository Service at National Institute of Oceanography (India)

Sathe, P.V.; Muraleedharan, P.M.

the sea surface air temperature from satellite derived sea surface humidity in the Indian Ocean. Using the insitu data on surface met parameters collected on board O.R.V. Sagar Kanya in the Indian Ocean over a period of 15 years, the relationship between...

Correlation between δ18O in precipitation and surface air temperature on different time-scale in China

International Nuclear Information System (INIS)

Zhang Lin; Chen Zongyu; Nie Zhenlong; Liu Fuliang; Jia Yankun; Zhang Xiangyang

2008-01-01

The relation between isotopic compositions of precipitation and surface air temperature provides a unique tool for paleoclimate studies, among which the relation between long term changes in δ 18 O of precipitation and surface air temperature at different stations or in a given location seems to be the most appropriate to paleoclimatic reconstructions. Analysis was conducted on monthly and annual mean δ 18 O content of precipitation and surface air temperature at spatial and fixed locations by using the data of China (1985-2002) in Global Network of Isotopes in Precipitation (GNIP) Database. This study shows that there is a positive correlation between δ 18 O of precipitation and surface air temperature for stations located in north of 34 degree-36 degree N latitudes. The seasonal δ 18 O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.034% degree C -1 . The δ 18 O-temperature gradient, however, derived from the long term annual mean data of 13 stations, is about 0.052% degree C -1 , which is substantially larger than the seasonal gradient. (authors)

Molecular Biological Characterization of Air Samples: A Survey of Four Strategically Important Regions

National Research Council Canada - National Science Library

Francesconi, Stephen

2003-01-01

.... In support of this requirement, the Joint Program Office for Biological Defense initiated an aggressive program incorporating the development of air-sampling and agent detecting devices, coined...

Protocol for Microplastics Sampling on the Sea Surface and Sample Analysis

Science.gov (United States)

Kovač Viršek, Manca; Palatinus, Andreja; Koren, Špela; Peterlin, Monika; Horvat, Petra; Kržan, Andrej

2016-01-01

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of scientific publications address microplastic pollution of the sea surface. The protocol below describes the methodology for sampling, sample preparation, separation and chemical identification of microplastic particles. A manta net fixed on an »A frame« attached to the side of the vessel was used for sampling. Microplastic particles caught in the cod end of the net were separated from samples by visual identification and use of stereomicroscopes. Particles were analyzed for their size using an image analysis program and for their chemical structure using ATR-FTIR and micro FTIR spectroscopy. The described protocol is in line with recommendations for microplastics monitoring published by the Marine Strategy Framework Directive (MSFD) Technical Subgroup on Marine Litter. This written protocol with video guide will support the work of researchers that deal with microplastics monitoring all over the world. PMID:28060297

Ambient air sampling of organic pollutants and heavy metals within the EU/93/AIR/22 PHARE Project

International Nuclear Information System (INIS)

Kocan, A.

1997-01-01

Within the framework of the project the concentrations of eight heavy metals, vapour mercury, seven polychlorinated dibenzo-p-dioxin's, ten polychlordibenzofuran congeners, eighteen polychlorinated biphenyls, two chlorinated pesticides (hexachlorobenzene, p,p'-DDE and p,p'-DDT), fourteen polycyclic aromatic hydrocarbons, forty-two volatile organic compounds, total suspended particles were analysed. The morphology characterization of collected airborne particles and bioassays aimed at the evaluation of the mutagenic potency of pollutants present in collected air were also performed. Ambient air heavy metals were caught on cellulose filters using the same type of the sampler used for semi-volatile compounds sampling and analysed by atomic spectrometry. Vapour mercury was trapped on gold sand packed in a tube through which about 280 L of ambient air during 24 hours were drawn. On-site analysis was performed by an atomic fluorescence analyzer. Inhalable air particles, i.e particles less than 10 μm in diameter were collected by a sampler equipped with a cascade impactor fractionating into five size fractions involving respirable (<3 μm) fractions. The morphology and composition of the respirable fractions was investigated by scanning electron microscopy and X-ray microanalysis

Continuous air monitor correlation to fixed air sample data at Los Alamos National Laboratory

International Nuclear Information System (INIS)

Whicker, J.J.

1993-01-01

Continuous air monitoring instruments (CAMS) deployed in laboratories in the TA-55 plutonium facility at Los Alamos National Laboratory (LANL) alarmed less than 33 percent of the time when fixed air sample measurements in the same laboratory showed integrated concentrations exceeding 500 DAC-hrs. The purpose of this study was to explore effects of non-instrument variables on alarm sensitivities for properly working CAMS. Non-instrument variables include air flow patterns, particle size of released material, and the energy of the release. Dilution Factors (DFs) for 21 airborne releases in various rooms and of different magnitudes were calculated and compared. The median DF for releases where the CAM alarmed was 13.1 while the median DF for releases where the CAM did not alarm was 179. Particle sizes ranged considerably with many particles larger than 10 μm. The cause of the release was found to be important in predicting if a CAM would alarm with releases from bagouts resulting in the greatest percentage of CAM alarms. The results of this study suggest that a two-component strategy for CAM placement at LANL be utilized. The first component would require CAMs at exhaust points in the rooms to provide for reliable detection for random release locations. The second component would require placing CAMs at locations where releases have historically been seen. Finally, improvements in CAM instrumentation is needed

Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

Energy Technology Data Exchange (ETDEWEB)

Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J., E-mail: rc.nardes@gmail.com, E-mail: ramonziosp@yahoo.com.br, E-mail: francissanches@gmail.com, E-mail: hamiltongamafilho@hotmail.com, E-mail: davi.oliveira@uerj.br, E-mail: marcelin@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Fisica. Departamento de Fisica Aplicada e Termodinamica

2015-07-01

Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

Determination of metals in air samples using X-Ray fluorescence associated the APDC preconcentration technique

International Nuclear Information System (INIS)

Nardes, Raysa C.; Santos, Ramon S.; Sanches, Francis A.C.R.A.; Gama Filho, Hamilton S.; Oliveira, Davi F.; Anjos, Marcelino J.

2015-01-01

Air pollution has become one of the leading quality degradation factors of life for people in large urban centers. Studies indicate that the suspended particulate matter in the atmosphere is directly associated with risks to public health, in addition, it can cause damage to fauna, flora and public / cultural patrimonies. The inhalable particulate materials can cause the emergence and / or worsening of chronic diseases related to respiratory system and other diseases, such as reduced physical strength. In this study, we propose a new method to measure the concentration of total suspended particulate matter (TSP) in the air using an impinger as an air cleaning apparatus, preconcentration with APDC and Total Reflection X-ray Fluorescence technique (TXRF) to analyze the heavy metals present in the air. The samples were collected from five random points in the city of Rio de Janeiro/Brazil. Analyses of TXRF were performed at the Brazilian Synchrotron Light Laboratory (LNLS). The technique proved viable because it was able to detect five important metallic elements to environmental studies: Cr, Fe, Ni, Cu and Zn. This technique presented substantial efficiency in determining the elementary concentration of air pollutants, in addition to low cost. It can be concluded that the metals analysis technique in air samples using an impinger as sample collection instrument associated with a complexing agent (APDC) was viable because it is a low-cost technique, moreover, it was possible the detection of five important metal elements in environmental studies associated with industrial emissions and urban traffic. (author)

Surface modification of thermoplastic poly(vinyl alcohol)/saponite nanocomposites via surface-initiated atom transfer radical polymerization enhanced by air dielectric discharges barrier plasma treatment

International Nuclear Information System (INIS)

Zhen Weijun; Lu Canhui

2012-01-01

To improve the water resistance of thermoplastic poly(vinyl alcohol)/saponite nanocomposites (TPVA), a simple two-step method was developed for the covalent immobilization of atom transfer radical polymerization (ATRP) initiators on the TPVA surfaces enhanced by air dielectric barrier discharges (DBD) plasma treatment, and hydrophobic poly(methyl methacrylate) (PMMA) brushes were then grafted onto the surface of TPVA via surface-initiated atom transfer radical polymerization (SI-ATRP). The chemical composition, morphology and hydrophobicity of the modified TPVA surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The water resistance of the surface-functionalized PMMA was evaluated by the contact angle and water adsorption method. It was shown that air DBD plasma treatment activated the TPVA surface and accelerated the immobilization of ATRP initiator on the TPVA surface. Compared with TPVA control, TPVA modified by SI-ATRP can be grafted well-defined and covalently tethered network PMMA brushes onto the surface and the hydrophobicity of TPVA were significantly enhanced.

Reliability Evaluation for the Surface to Air Missile Weapon Based on Cloud Model

Directory of Open Access Journals (Sweden)

Deng Jianjun

2015-01-01

Full Text Available The fuzziness and randomness is integrated by using digital characteristics, such as Expected value, Entropy and Hyper entropy. The cloud model adapted to reliability evaluation is put forward based on the concept of the surface to air missile weapon. The cloud scale of the qualitative evaluation is constructed, and the quantitative variable and the qualitative variable in the system reliability evaluation are corresponded. The practical calculation result shows that it is more effective to analyze the reliability of the surface to air missile weapon by this way. The practical calculation result also reflects the model expressed by cloud theory is more consistent with the human thinking style of uncertainty.

Computer simulation of RBS spectra from samples with surface roughness

Energy Technology Data Exchange (ETDEWEB)

Malinský, P., E-mail: malinsky@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v. v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Hnatowicz, V., E-mail: hnatowicz@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v. v. i., 250 68 Rez (Czech Republic); Macková, A., E-mail: mackova@ujf.cas.cz [Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, v. v. i., 250 68 Rez (Czech Republic); Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic)

2016-03-15

A fast code for the simulation of common RBS spectra including surface roughness effects has been written and tested on virtual samples comprising either a rough layer deposited on a smooth substrate or smooth layer deposited on a rough substrate and simulated at different geometries. The sample surface or interface relief has been described by a polyline and the simulated RBS spectrum has been obtained as the sum of many particular spectra from randomly chosen particle trajectories. The code includes several procedures generating virtual samples with random and regular (periodical) roughness. The shape of the RBS spectra has been found to change strongly with increasing sample roughness and an increasing angle of the incoming ion beam.

Man-made radioactivity of surface air and precipitation Munich-Neuherberg 1970-1975

International Nuclear Information System (INIS)

Hoetzl, H.; Rosner, G.; Winkler, R.

1976-07-01

The activity concentration of a number of artificial radionuclides and of Be 7 in surface air and the deposition of these nuclides to the ground by the precipitation is measured since 1970 resp. 1971 at Neuherberg near Munich. Air dust filters are compressed to give a pellet and precipitation is evaporated to a small volume before γ-spectrometry using a Ge(Li)-detector. After ashing of the samples Pusup(238, 239, 240) and Fe 55 are separated radiochemically and measured by alpha respectively X-ray spectrometry. The results, presented as monthly mean resp. sum values, are discussed and compared with results published by other authors (HASL, UKAEA, PTB, DWD a.o.). The contribution of artificial radioactivity to the radiation exposure from fallout nuclides during the years 1970 to 1975 was very low. Their concentration levels led to values of the annual intake, which are far beyond the admissible values according to the new Radiation Protection Ordinance of the FRG. With regard to the intake by inhalation Pu 239 is the most important of all observed nuclides, whereas in the case of ingestion Sr 90 is the critical nuclide. At this time the level of the activity concentration is mainly represented by the residual radioactivity from nuclear bomb tests. A continuous control is necessary because of the growth of nuclear power production and the increasing use of radionuclides. (orig.) [de

Actinide nuclides in environmental air and precipitation samples after the Chernobyl accident

Energy Technology Data Exchange (ETDEWEB)

Rosner, G.; Hoetzl, H.; Winkler, R. (Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen (West Germany))

1988-01-01

The present paper describes the analysis of isotopes of uranium, neptunium, plutonium, americium and curium, in air and deposition samples taken at our laboratory site 10 km north of Munich, subsequent to the Chernobyl accident. Uranium-234, {sup 237}U, {sup 238}U, {sup 239}Np, {sup 238}Pu, {sup 239+240}Pu and {sup 242}Cm have been identified and upper limits of detection have been established for {sup 241}Am and {sup 244}Cm. Deposition and air concentration values are discussed. 12 refs., 1 fig., 2 tabs.

Comparison of indoor air sampling and dust collection methods for fungal exposure assessment using quantitative PCR

Science.gov (United States)

Evaluating fungal contamination indoors is complicated because of the many different sampling methods utilized. In this study, fungal contamination was evaluated using five sampling methods and four matrices for results. The five sampling methods were a 48 hour indoor air sample ...

Scheduling whole-air samples above the Trade Wind Inversion from SUAS using real-time sensors

Science.gov (United States)

Freer, J. E.; Greatwood, C.; Thomas, R.; Richardson, T.; Brownlow, R.; Lowry, D.; MacKenzie, A. R.; Nisbet, E. G.

2015-12-01

Small Unmanned Air Systems (SUAS) are increasingly being used in science applications for a range of applications. Here we explore their use to schedule the sampling of air masses up to 2.5km above ground using computer controlled bespoked Octocopter platforms. Whole-air sampling is targeted above, within and below the Trade Wind Inversion (TWI). On-board sensors profiled the TWI characteristics in real time on ascent and, hence, guided the altitudes at which samples were taken on descent. The science driver for this research is investigation of the Southern Methane Anomaly and, more broadly, the hemispheric-scale transport of long-lived atmospheric tracers in the remote troposphere. Here we focus on the practical application of SUAS for this purpose. Highlighting the need for mission planning, computer control, onboard sensors and logistics in deploying such technologies for out of line-of-sight applications. We show how such a platform can be deployed successfully, resulting in some 60 sampling flights within a 10 day period. Challenges remain regarding the deployment of such platforms routinely and cost-effectively, particularly regarding training and support. We present some initial results from the methane sampling and its implication for exploring and understanding the Southern Methane Anomaly.

Seasonal fluctuations of the uranium and thorium contents in aerosols in surface air

International Nuclear Information System (INIS)

Kolb, W.

1985-01-01

An estimate in the UNSCEAR report the only source considered for the uranium and thorium contents is ground dust. A significant portion of the aerosols, however, comes from chimneys. Aerosol samples taken monthly in Brunswick, Berlin, Skibotn (Northern Norway) were, therefore, scrutinized alpha-spectrometrically for U-238, U-234, Th-230, and Th-232. The activity concentration in surface air of Northern Norway is only about 30 nBq/cm 3 . In Brunswick and Berlin, the concentration was higher by a factor of one to two due to the higher specific activity of the mineral aerosols. Significant differences of the isotope ratios allow conclusions as to the origin of the aerosols. The activity concentrations measured and their seasonal fluctuations must be taken into account in the evaluation of environment monitoring of nuclear fuel factories. (orig./HP) [de

Cracks and nanodroplets produced on tungsten surface samples by dense plasma jets

Science.gov (United States)

Ticoş, C. M.; Galaţanu, M.; Galaţanu, A.; Luculescu, C.; Scurtu, A.; Udrea, N.; Ticoş, D.; Dumitru, M.

2018-03-01

Small samples of 12.5 mm in diameter made from pure tungsten were exposed to a dense plasma jet produced by a coaxial plasma gun operated at 2 kJ. The surface of the samples was analyzed using a scanning electron microscope (SEM) before and after applying consecutive plasma shots. Cracks and craters were produced in the surface due to surface tensions during plasma heating. Nanodroplets and micron size droplets could be observed on the samples surface. An energy-dispersive spectroscopy (EDS) analysis revealed that the composition of these droplets coincided with that of the gun electrode material. Four types of samples were prepared by spark plasma sintering from powders with the average particle size ranging from 70 nanometers up to 80 μm. The plasma power load to the sample surface was estimated to be ≈4.7 MJ m-2 s-1/2 per shot. The electron temperature and density in the plasma jet had peak values 17 eV and 1.6 × 1022 m-3, respectively.

Rapid extraction and assay of uranium from environmental surface samples

Energy Technology Data Exchange (ETDEWEB)

Barrett, Christopher A.; Chouyyok, Wilaiwan; Speakman, Robert J.; Olsen, Khris B.; Addleman, Raymond Shane

2017-10-01

Extraction methods enabling faster removal and concentration of uranium compounds for improved trace and low-level assay are demonstrated for standard surface sampling material in support of nuclear safeguards efforts, health monitoring, and other nuclear analysis applications. A key problem with the existing surface sampling swipes is the requirement for complete digestion of sample and sampling matrix. This is a time-consuming and labour-intensive process that limits laboratory throughput, elevates costs, and increases background levels. Various extraction methods are explored for their potential to quickly and efficiently remove different chemical forms of uranium from standard surface sampling material. A combination of carbonate and peroxide solutions is shown to give the most rapid and complete form of uranyl compound extraction and dissolution. This rapid extraction process is demonstrated to be compatible with standard inductive coupled plasma mass spectrometry methods for uranium isotopic assay as well as screening techniques such as x-ray fluorescence. The general approach described has application beyond uranium to other analytes of nuclear forensic interest (e.g., rare earth elements and plutonium) as well as heavy metals for environmental and industrial hygiene monitoring.

Interpolating and sampling sequences in finite Riemann surfaces

OpenAIRE

Ortega-Cerda, Joaquim

2007-01-01

We provide a description of the interpolating and sampling sequences on a space of holomorphic functions on a finite Riemann surface, where a uniform growth restriction is imposed on the holomorphic functions.

Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model.

Science.gov (United States)

Garcia, L; Bedos, C; Génermont, S; Braud, I; Cellier, P

2011-09-01

Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization

Effects of air dielectric barrier discharge plasma treatment time on surface properties of PBO fiber

International Nuclear Information System (INIS)

Wang Qian; Chen Ping; Jia Caixia; Chen, Mingxin; Li Bin

2011-01-01

In this paper, the effects of air dielectric barrier discharge (DBD) plasma treatment time on surface properties of poly(p-phenylene benzobisoxazole) (PBO) fiber were investigated. The surface characteristics of PBO fiber before and after the plasma treatments were analyzed by dynamic contact angle (DCA) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). DCA measurements indicated that the surface wettability of PBO fiber was improved significantly by increasing the fiber surface free energy via air DBD plasma treatments. The results were confirmed by the improvement of adhesion of a kind of thermoplastic resin to PBO fiber which was observed by SEM, showing that more resin was adhering evenly to the fiber surface. AFM measurement revealed that the surface topography of PBO fiber became more complicated and the surface roughness was greatly enhanced after the plasma treatments, and XPS analysis showed that some new polar groups (e.g. -O-C=O) were introduced on plasma treated PBO fiber surface. The results of this study also showed that the surface properties of PBO fiber changed with the elongation of plasma treatment time.

Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

Science.gov (United States)

Zhao, Luxiang; Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong

2018-05-01

A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

Molecular dynamics simulations of water on a hydrophilic silica surface at high air pressures

DEFF Research Database (Denmark)

Zambrano, H.A.; Walther, Jens Honore; Jaffe, R.L.

2014-01-01

Wepresent a force field forMolecular Dynamics (MD) simulations ofwater and air in contactwith an amorphous silica surface. We calibrate the interactions of each species present in the systemusing dedicated criteria such as the contact angle of a water droplet on a silica surface, and the solubility...

Molecular Dynamics Simulation of Water Nanodroplets on Silica Surfaces at High Air Pressures

DEFF Research Database (Denmark)

Zambrano, Harvey A; Jaffe, Richard Lawrence; Walther, Jens Honore

2010-01-01

e.g., nanobubbles. In the present work we study the role of air on the wetting of hydrophilic systems. We conduct molecular dynamics simulations of a water nanodroplet on an amorphous silica surface at different air pressures. The interaction potentials describing the silica, water, and air......Silicon dioxides-water systems are abundant in nature and play fundamental roles in a diversity of novel science and engineering applications. Although extensive research has been devoted to study the nature of the interaction between silica and water a complete understanding of the system has...... perform extensive simulations of the water- air equilibrium and calibrate the water-air interaction to match the experimental solubility of N2 and O2 in water. For the silica-water system we calibrate the water-silica interaction to match the experimental contact angle of 27º. We subsequently study...

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH4 and CO2

Directory of Open Access Journals (Sweden)

O. Membrive

2017-06-01

Full Text Available An original and innovative sampling system called AirCore was presented by NOAA in 2010 (Karion et al., 2010. It consists of a long (>  100 m and narrow (<  1 cm stainless steel tube that can retain a profile of atmospheric air. The captured air sample has then to be analyzed with a gas analyzer for trace mole fraction. In this study, we introduce a new AirCore aiming to improve resolution along the vertical with the objectives to (i better capture the vertical distribution of CO2 and CH4, (ii provide a tool to compare AirCores and validate the estimated vertical resolution achieved by AirCores. This (high-resolution AirCore-HR consists of a 300 m tube, combining 200 m of 0.125 in. (3.175 mm tube and a 100 m of 0.25 in. (6.35 mm tube. This new configuration allows us to achieve a vertical resolution of 300 m up to 15 km and better than 500 m up to 22 km (if analysis of the retained sample is performed within 3 h. The AirCore-HR was flown for the first time during the annual StratoScience campaign from CNES in August 2014 from Timmins (Ontario, Canada. High-resolution vertical profiles of CO2 and CH4 up to 25 km were successfully retrieved. These profiles revealed well-defined transport structures in the troposphere (also seen in CAMS-ECMWF high-resolution forecasts of CO2 and CH4 profiles and captured the decrease of CO2 and CH4 in the stratosphere. The multi-instrument gondola also carried two other low-resolution AirCore-GUF that allowed us to perform direct comparisons and study the underlying processing method used to convert the sample of air to greenhouse gases vertical profiles. In particular, degrading the AirCore-HR derived profiles to the low resolution of AirCore-GUF yields an excellent match between both sets of CH4 profiles and shows a good consistency in terms of vertical structures. This fully validates the theoretical vertical resolution achievable by AirCores. Concerning CO2 although a

Dust Load on Surfaces in Animal Buildings

DEFF Research Database (Denmark)

Lengweiler, P.; Strøm, J. S.; Takai, H.

To investigate the physical process of particle deposition on and resuspension from surfaces in animal buildings, a test facility and a sampling method is established. The influences of surface orientation and air turbulence and velocity just as other parameters on the dust load on a surface...

Evaluation of entrance surface air kerma in pediatric chest radiography

Science.gov (United States)

Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J. L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

2014-11-01

The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior-posterior (AP) and posterior-anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0-1 y, 1-5 y, 5-10 y, and 10-15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels.

Single-shot femtosecond laser ablation of gold surface in air and isopropyl alcohol

Science.gov (United States)

Kudryashov, S. I.; Saraeva, I. N.; Lednev, V. N.; Pershin, S. M.; Rudenko, A. A.; Ionin, A. A.

2018-05-01

Single-shot IR femtosecond-laser ablation of gold surfaces in ambient air and liquid isopropyl alcohol was studied by scanning electron microscopy characterization of crater topographies and time-resolved optical emission spectroscopy of ablative plumes in regimes, typical for non-filamentary and non-fragmentation laser production of nanoparticle sols. Despite one order of magnitude shorter (few nanoseconds) lifetimes and almost two orders of magnitude lower intensities of the quenched ablative plume emission in the alcohol ambient at the same peak laser fluence, craters for the dry and wet conditions appeared with rather similar nanofoam-like spallative topographies and the same thresholds. These facts envision the underlying surface spallation as one of the basic ablation mechanisms relevant for both dry and wet advanced femtosecond laser surface nano/micro-machining and texturing, as well as for high-throughput femtosecond laser ablative production of colloidal nanoparticles by MHz laser-pulse trains via their direct nanoscale jetting from the nanofoam in air and fluid environments.

High-resolution real-time optical studies of radiological air sample filtration processes in an environmental continuous air monitor

Science.gov (United States)

Rodgers, John C.; Wasiolek, Piotr T.; Schery, Stephen D.; Alcantara, Raul E.

1999-01-01

The need for a continuous air monitor capable of quick and accurate measurements of airborne radioactivity in close proximity to the work environment during waste management, site restoration, and D&D operations led to the Los Alamos National Laboratory development of an environmental continuous air monitor (ECAM). Monitoring the hostile work environment of waste recovery, for example, presents unique challenges for detector design for detectors previously used for the clean room conditions of the typical plutonium laboratory. The environmental and atmospheric conditions (dust, high wind, etc.) influence aerosol particle penetration into the ECAM sampling head as well as the build-up of deposits on the ECAM filter.

Size selective isocyanate aerosols personal air sampling using porous plastic foams

International Nuclear Information System (INIS)

Cong Khanh Huynh; Trinh Vu Duc

2009-01-01

As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

Cold air plasma to decontaminate inanimate surfaces of the hospital environment.

Science.gov (United States)

Cahill, Orla J; Claro, Tânia; O'Connor, Niall; Cafolla, Anthony A; Stevens, Niall T; Daniels, Stephen; Humphreys, Hilary

2014-03-01

The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated the in vitro use of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli, and Acinetobacter baumannii were applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producing E. coli, and log 1.7 for A. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment.

Impact of preferential sampling on exposure prediction and health effect inference in the context of air pollution epidemiology.

Science.gov (United States)

Lee, A; Szpiro, A; Kim, S Y; Sheppard, L

2015-06-01

Preferential sampling has been defined in the context of geostatistical modeling as the dependence between the sampling locations and the process that describes the spatial structure of the data. It can occur when networks are designed to find high values. For example, in networks based on the U.S. Clean Air Act monitors are sited to determine whether air quality standards are exceeded. We study the impact of the design of monitor networks in the context of air pollution epidemiology studies. The effect of preferential sampling has been illustrated in the literature by highlighting its impact on spatial predictions. In this paper, we use these predictions as input in a second stage analysis, and we assess how they affect health effect inference. Our work is motivated by data from two United States regulatory networks and health data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. The two networks were designed to monitor air pollution in urban and rural areas respectively, and we found that the health analysis results based on the two networks can lead to different scientific conclusions. We use preferential sampling to gain insight into these differences. We designed a simulation study, and found that the validity and reliability of the health effect estimate can be greatly affected by how we sample the monitor locations. To better understand its effect on second stage inference, we identify two components of preferential sampling that shed light on how preferential sampling alters the properties of the health effect estimate.

Impact of preferential sampling on exposure prediction and health effect inference in the context of air pollution epidemiology

Science.gov (United States)

Lee, A.; Szpiro, A.; Kim, S.Y.; Sheppard, L.

2018-01-01

Summary Preferential sampling has been defined in the context of geostatistical modeling as the dependence between the sampling locations and the process that describes the spatial structure of the data. It can occur when networks are designed to find high values. For example, in networks based on the U.S. Clean Air Act monitors are sited to determine whether air quality standards are exceeded. We study the impact of the design of monitor networks in the context of air pollution epidemiology studies. The effect of preferential sampling has been illustrated in the literature by highlighting its impact on spatial predictions. In this paper, we use these predictions as input in a second stage analysis, and we assess how they affect health effect inference. Our work is motivated by data from two United States regulatory networks and health data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. The two networks were designed to monitor air pollution in urban and rural areas respectively, and we found that the health analysis results based on the two networks can lead to different scientific conclusions. We use preferential sampling to gain insight into these differences. We designed a simulation study, and found that the validity and reliability of the health effect estimate can be greatly affected by how we sample the monitor locations. To better understand its effect on second stage inference, we identify two components of preferential sampling that shed light on how preferential sampling alters the properties of the health effect estimate. PMID:29576734

Radiative warming of the air observed near a bare-soil surface on calm clear nights

International Nuclear Information System (INIS)

Sang, N.; Kobayahsi, T.

1999-01-01

The radiative flux in the lowest three meters above a bare-soil surface was directly measured on calm nights with little cloud cover. Although divergence of upward radiative flux occurred above 1m, convergence was often observed between 0.2m and 1m all through the night. Almost the same results were obtained for the net flux except that the transitional height between divergence and convergence was some tens of centimeters, which means that radiative warming occurred just above the bare-soil surface during the night. This phenomenon can be explained by postulating that cold air is produced by conduction at the surface of small heat-insulated projections (HIPs) such as soil grains on the ground surface, while the ground releases the heat stored during the day by radiation through the pores between HIPs and warms the air immediately above the surface at night. This “HIP hypothesis” can also account for the so-called “raised minimum (RM)” phenomenon. (author)

The surface activity of purified ocular mucin at the air-liquid interface and interactions with meibomian lipids.

Science.gov (United States)

Millar, Thomas J; Tragoulias, Sophia T; Anderton, Philip J; Ball, Malcolm S; Miano, Fausto; Dennis, Gary R; Mudgil, Poonam

2006-01-01

Ocular mucins are thought to contribute to the stability of the tear film by reducing surface tension. The purpose of this study was to compare the effect of different mucins and hyaluronic acid (HA) alone and mixed with meibomian lipids on the surface pressure at an air-liquid interface. A Langmuir trough and Wilhelmy balance were used to measure and compare the surface activity of bovine submaxillary gland mucin (BSM), purified BSM, purified bovine ocular mucin and HA, and mixtures of these with meibomian lipids, phosphatidylcholine, and phosphatidylglycerol. Their appearance at the surface of an air-buffer interface was examined using epifluorescence microscopy. Purified ocular mucin had no surface activity even at concentrations that were 100 times more than normally occur in tears. By contrast, commercial BSM caused changes to surface pressure that were concentration dependent. The surface pressure-area profiles showed surface activity with maximum surface pressures of 12.3-22.5 mN/m depending on the concentration. Purified BSM showed no surface activity at low concentrations, whereas higher concentrations reached a maximum surface pressure of 25 mN/m. HA showed no surface activity, at low or high concentrations. Epifluorescence showed that the mucins were located at the air-buffer interface and changed the appearance of lipid films. Purified bovine ocular mucin and HA have no surface activity. However, despite having no surface activity in their own right, ocular mucins are likely to be present at the surface of the tear film, where they cause an increase in surface pressure by causing a compression of the lipids (a reorganization of the lipids) and alter the viscoelastic properties at the surface.

Investigation of ammonia air-surface exchange processes in a ...

Science.gov (United States)

Recent assessments of atmospheric deposition in North America note the increasing importance of reduced (NHx = NH3 + NH4+) forms of nitrogen (N) relative to oxidized forms. This shift in in the composition of inorganic nitrogen deposition has both ecological and policy implications. Deposition budgets developed from inferential models applied at the landscape scale, as well as regional and global chemical transport models, indicate that NH3 dry deposition contributes a significant portion of inorganic N deposition in many areas. However, the bidirectional NH3 flux algorithms employed in these models have not been extensively evaluated for North American conditions (e.g, atmospheric chemistry, meteorology, biogeochemistry). Further understanding of the processes controlling NH3 air-surface exchange in natural systems is critically needed. Based on preliminary results from the Southern Appalachian Nitrogen Deposition Study (SANDS), this presentation examines processes of NH3 air-surface exchange in a deciduous montane forest at the Coweeta Hydrologic Laboratory in western North Carolina. A combination of measurements and modeling are used to investigate net fluxes of NH3 above the forest and sources and sinks of NH3 within the canopy and forest floor. Measurements of biogeochemical NH4+ pools are used to characterize emission potential and NH3 compensation points of canopy foliage (i.e., green vegetation), leaf litter, and soil and their relation to NH3 fluxes

Surface ignition behaviors of methane–air mixture in a gas oven burner

International Nuclear Information System (INIS)

Ryu, Jungwan; Kwon, Jongseo; Kim, Ryanggyun; Kim, Minseong; Kim, Youngsoo; Jeon, Chunghwan; Song, Juhun

2014-01-01

In a gas oven burner, commonly used as a residential appliance, a surface igniter is a critical component for creating a pilot flame near the surface that can propagate safely back to the nozzle of the burner. The igniter should meet critical operating requirements: a lower surface temperature needed to ignite a methane–air mixture and a stable/safe ignition sustained. Otherwise, such failure would result in an instantaneous peak in carbon monoxide emission and a safety hazard inside a closed oven. Several theoretical correlations have been used to predict ignition temperature as well as the critical ignition/extinction limit for a stagnation flow ignition. However, there have only been a few studies on ignition modes or relevant stability analysis, and therefore a more detailed examination of the transient ignition process is required. In this study, a high-speed flame visualization technique with temperature measurement was employed to reveal a surface ignition phenomenon and subsequent flame propagation of a cold combustible methane–air mixture in a gas oven burner. The operating parameters were the temperature–time history of the igniter surface, mixture velocity, and the distance of the igniter from the nozzle. The surface ignition temperatures were analyzed for such parameters under a safe ignition mode, while several abnormal modes leading to ignition failure were also recognized. - Highlights: •We revealed a surface ignition behavior of combustible mixture in gas oven burner. •We employed a flame visualization technique with temperature measurement. •We evaluated effects of parameters such as lifetime, mixture velocity and igniter distance. •We recognized several abnormal modes leading to ignition failure

An assessment of air sampling location for stack monitoring in nuclear facility

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Bok [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Tae Hyoung; Lee, Jong Il; Kim, Bong Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-06-15

In this study, air sampling locations in the stack of the Advanced Fuel Science Building (AFSB) at the Korea Atomic Energy Research Institute (KAERI) were assessed according to the ANSI/HPS N13.1-1999 specification. The velocity profile, flow angle and 10 μm aerosol particle profile at the cross-section as functions of stack height L and stack diameter D (L/D) were assessed according to the sampling location criteria using COMSOL. The criteria for the velocity profile were found to be met at 5 L/D or more for the height, and the criteria for the average flow angle were met at all locations through this assessment. The criteria for the particle profile were met at 5 L/D and 9 L/D. However, the particle profile at the cross-section of each sampling location was found to be non-uniform. In order to establish uniformity of the particle profile, a static mixer and a perimeter ring were modeled, after which the degrees of effectiveness of these components were compared. Modeling using the static mixer indicated that the sampling locations that met the criteria for the particle profile were 5-10 L/D. When modeling using the perimeter ring, the sampling locations that met the criteria for particle profile were 5 L/D and 7-10 L/D. The criteria for the velocity profile and the average flow angle were also met at the sampling locations that met the criteria for the particle profile. The methodologies used in this study can also be applied during assessments of air sampling locations when monitoring stacks at new nuclear facilities as well as existing nuclear facilities.

Effect of environmental dust particles on laser textured yttria-stabilized zirconia surface in humid air ambient

Science.gov (United States)

Yilbas, B. S.; Ali, H.; Al-Sharafi, A.; Al-Sulaiman, F.; Karatas, C.

2018-05-01

Zirconium nitride is used as a selective surface for concentrated solar heating applications and one of the methods to form a zirconium nitride is texturing of zirconia surface by a high intensity laser beam under high pressure nitrogen gas environment. Laser texturing also provides hydrophobic surface characteristics via forming micro/nano pillars at the surface; however, environmental dust settlement on textured surface influences the surface characteristics significantly. In the present study, laser texturing of zirconia surface and effects of the dust particles on the textured surface in a humid air ambient are investigated. Analytical tools are used to assess the morphological changes on the laser textured surface prior and after the dust settlement in the humid air ambient. It is found that laser textured surface has hydrophobic characteristics. The mud formed during condensate of water on the dust particles alters the characteristics of the laser textured surface. The tangential force required to remove the dry mud from the textured surface remains high; in which case, the dried liquid solution at the mud-textured surface interface is responsible for the strong adhesion of the dry mud on the textured surface. The textured surface becomes hydrophilic after the dry mud was removed from the surface by a desalinated water jet.

Observed Screen (Air) and GCM Surface/Screen Temperatures: Implications for Outgoing Longwave Fluxes at the Surface.

Science.gov (United States)

Garratt, J. R.

1995-05-01

There is direct evidence that excess net radiation calculated in general circulation models at continental surfaces [of about 11-17 W m2 (20%-27%) on an annual ~1 is not only due to overestimates in annual incoming shortwave fluxes [of 9-18 W m2 (6%-9%)], but also to underestimates in outgoing longwave fluxes. The bias in the outgoing longwave flux is deduced from a comparison of screen-air temperature observations, available as a global climatology of mean monthly values, and model-calculated surface and screen-air temperatures. An underestimate in the screen temperature computed in general circulation models over continents, of about 3 K on an annual basis, implies an underestimate in the outgoing longwave flux, averaged in six models under study, of 11-15 W m2 (3%-4%). For a set of 22 inland stations studied previously, the residual bias on an annual basis (the residual is the net radiation minus incoming shortwave plus outgoing longwave) varies between 18 and 23 W m2 for the models considered. Additional biases in one or both of the reflected shortwave and incoming longwave components cannot be ruled out.

Aerial sampling using drones for measuring trace gases

Science.gov (United States)

Chang, Chih-Chung; Wang, Jia-Lin; Chang, Chih-Yuan; Lin, Ming-Ren; Ou-Yang, Chang-Feng; Pan, Xiang-Xu; Lin, Neng-Huei

2017-04-01

Aerial and ground-level samples were simultaneously collected at the northern tip of Taiwan, Cape Fuguei, which is commonly served as a receptor site to receive air parcels from East Asia, Asian continent, the northwest Pacific Ocean and the island of Taiwan itself. Both aerial and surface samples were analyzed for 106 volatile organic compounds (VOCs) and divided into three categories as follows: 1. the total concentrations of 106 VOC (T-VOC) at 300-m height that are lower than the T-VOC level at the surface (Category A), 2. T-VOC concentrations at 300-m that are higher than those at the surface (Category B), and 3. comparable concentrations (Category C). Ten VOCs were exploited as tracers for a variety of emission sources linking to possible sources and transport routes of airborne pollutants. The first two categories A and B showed significant differences in the observed composition and concentrations of tracers between aerial and ground-level samples, implying that the pollutants at different heights may have resulted from different sources and poor air mixing, despite only a 300-m difference in vertical height. In contrast, Category C showed good vertical mixing, as indicated by the comparable concentrations between the aerial and surface measurements. Since the three categories occurred in specific meteorological conditions (between, prior to, and after cold fronts), respectively, it suggests that varied prevailing meteorology controlled the distribution and transport of airborne pollutants. Unlike sampling commonly performed at the surface, this study uses aerial sampling to demonstrate that layered structures under different meteorological conditions. Sampling aloft in lower boundary layer avoids samples being over-influenced by the close-by surface sources such as traffic to reveal signatures of a broader region.

Significant OH production under surface cleaning and air cleaning conditions: Impact on indoor air quality.

Science.gov (United States)

Carslaw, N; Fletcher, L; Heard, D; Ingham, T; Walker, H

2017-11-01

We report measurements of hydroxyl (OH) and hydroperoxy (HO 2 ) radicals made by laser-induced fluorescence spectroscopy in a computer classroom (i) in the absence of indoor activities (ii) during desk cleaning with a limonene-containing cleaner (iii) during operation of a commercially available "air cleaning" device. In the unmanipulated environment, the one-minute averaged OH concentration remained close to or below the limit of detection (6.5×10 5  molecule cm -3 ), whilst that of HO 2 was 1.3×10 7  molecule cm -3 . These concentrations increased to ~4×10 6 and 4×10 8  molecule cm -3 , respectively during desk cleaning. During operation of the air cleaning device, OH and HO 2 concentrations reached ~2×10 7 and ~6×10 8  molecule cm -3 respectively. The potential of these OH concentrations to initiate chemical processing is explored using a detailed chemical model for indoor air (the INDCM). The model can reproduce the measured OH and HO 2 concentrations to within 50% and often within a few % and demonstrates that the resulting secondary chemistry varies with the cleaning activity. Whilst terpene reaction products dominate the product composition following surface cleaning, those from aromatics and other VOCs are much more important during the use of the air cleaning device. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The surface emissions trap: a new approach in indoor air purification.

Science.gov (United States)

Markowicz, Pawel; Larsson, Lennart

2012-11-01

A new device for stopping or reducing potentially irritating or harmful emissions from surfaces indoors is described. The device is a surface emissions trap prototype and consists of an adsorbent sheet with a semipermeable barrier surrounded by two thin nonwoven layers. The trap may be applied directly at the source of the emissions e.g. at moisture-affected floors and walls, surfaces contaminated by chemical spills etc. This results in an immediate stop or reduction of the emitting pollutants. The trap has a very low water vapor resistance thus allowing drying of wet surfaces. In laboratory experiments typically 98% reduction of air concentrations of volatile organic compounds and a virtually total reduction of mold particle-associated mycotoxins was observed. The surface emissions trap may represent a convenient and efficient way of restoring indoor environments polluted by microbial and other moisture-associated emissions. Copyright © 2012 Elsevier B.V. All rights reserved.

Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis

International Nuclear Information System (INIS)

MULKEY, C.H.

1999-01-01

This document describes the results of the data quality objective (DQO) process undertaken to define data needs for state and federal requirements associated with toxic, hazardous, and/or radiological air emissions under the jurisdiction of the River Protection Project (RPP). Hereafter, this document is referred to as the Air DQO. The primary drivers for characterization under this DQO are the regulatory requirements pursuant to Washington State regulations, that may require sampling and analysis. The federal regulations concerning air emissions are incorporated into the Washington State regulations. Data needs exist for nonradioactive and radioactive waste constituents and characteristics as identified through the DQO process described in this document. The purpose is to identify current data needs for complying with regulatory drivers for the measurement of air emissions from RPP facilities in support of air permitting. These drivers include best management practices; similar analyses may have more than one regulatory driver. This document should not be used for determining overall compliance with regulations because the regulations are in constant change, and this document may not reflect the latest regulatory requirements. Regulatory requirements are also expected to change as various permits are issued. Data needs require samples for both radionuclides and nonradionuclide analytes of air emissions from tanks and stored waste containers. The collection of data is to support environmental permitting and compliance, not for health and safety issues

Environmental and emergency response capabilities of Los Alamos Scientific Laboratory's radiological air sampling program

International Nuclear Information System (INIS)

Gunderson, T.C.

1980-05-01

Environmental and emergency response radiological air sampling capabilities of the Environmental Surveillance Group at Los Alamos Scientific Laboratory are described. The air sampling program provides a supplementary check on the adequacy of containment and effluent controls, determines compliance with applicable protection guides and standards, and assesses potential environmental impacts on site environs. It also allows evaluation of potential individual and total population doses from airborne radionuclides that may be inhaled or serve as a source of external radiation. The environmental program is sufficient in scope to detect fluctuations and long-term trends in atmospheric levels of radioactivity originating onsite. The emergency response capabilities are designed to respond to both onsite unplanned releases and atmospheric nuclear tests

Gaussian process based intelligent sampling for measuring nano-structure surfaces

Science.gov (United States)

Sun, L. J.; Ren, M. J.; Yin, Y. H.

2016-09-01

Nanotechnology is the science and engineering that manipulate matters at nano scale, which can be used to create many new materials and devices with a vast range of applications. As the nanotech product increasingly enters the commercial marketplace, nanometrology becomes a stringent and enabling technology for the manipulation and the quality control of the nanotechnology. However, many measuring instruments, for instance scanning probe microscopy, are limited to relatively small area of hundreds of micrometers with very low efficiency. Therefore some intelligent sampling strategies should be required to improve the scanning efficiency for measuring large area. This paper presents a Gaussian process based intelligent sampling method to address this problem. The method makes use of Gaussian process based Bayesian regression as a mathematical foundation to represent the surface geometry, and the posterior estimation of Gaussian process is computed by combining the prior probability distribution with the maximum likelihood function. Then each sampling point is adaptively selected by determining the position which is the most likely outside of the required tolerance zone among the candidates and then inserted to update the model iteratively. Both simulationson the nominal surface and manufactured surface have been conducted on nano-structure surfaces to verify the validity of the proposed method. The results imply that the proposed method significantly improves the measurement efficiency in measuring large area structured surfaces.

Monte Carlo simulation of air sampling methods for the measurement of radon decay products.

Science.gov (United States)

Sima, Octavian; Luca, Aurelian; Sahagia, Maria

2017-08-01

A stochastic model of the processes involved in the measurement of the activity of the 222 Rn decay products was developed. The distributions of the relevant factors, including air sampling and radionuclide collection, are propagated using Monte Carlo simulation to the final distribution of the measurement results. The uncertainties of the 222 Rn decay products concentrations in the air are realistically evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Time-resolved imaging of a compressible air disc under a drop impacting on a solid surface

KAUST Repository

Li, Erqiang; Thoroddsen, Sigurdur T

2015-01-01

When a drop impacts on a solid surface, its rapid deceleration is cushioned by a thin layer of air, which leads to the entrapment of a bubble under its centre. For large impact velocities the lubrication pressure in this air layer becomes large

Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

International Nuclear Information System (INIS)

Barnett, J.M.

2008-01-01

Since the mid-1980s the Pacific Northwest National Laboratory (PNNL) has used a value of 0.85 as a correction factor for the self absorption of activity of particulate radioactive air samples. More recently, an effort was made to evaluate the current particulate radioactive air sample filters (Versapor(reg s ign) 3000) used at PNNL for self absorption effects. There were two methods used in the study, (1) to compare the radioactivity concentration by direct gas-flow proportional counting of the filter to the results obtained after acid digestion of the filter and counting again by gas-flow proportional detection and (2) to evaluate sample filters by high resolution visual/infrared microscopy to determine the depth of material loading on or in the filter fiber material. Sixty samples were selected from the archive for acid digestion in the first method and about 30 samples were selected for high resolution visual/infrared microscopy. Mass loading effects were also considered. From the sample filter analysis, large error is associated with the average self absorption factor, however, when the data is compared directly one-to-one, statistically, there appears to be good correlation between the two analytical methods. The mass loading of filters evaluated was <0.2 mg cm-2 and was also compared against other published results. The microscopy analysis shows the sample material remains on the top of the filter paper and does not imbed into the filter media. Results of the microscopy evaluation lead to the conclusion that there is not a mechanism for significant self absorption. The overall conclusion is that self-absorption is not a significant factor in the analysis of filters used at PNNL for radioactive air stack sampling of radionuclide particulates and that an applied correction factor is conservative in determining overall sample activity. A new self absorption factor of 1.0 is recommended

Interaction Mechanisms between Air Bubble and Molybdenite Surface: Impact of Solution Salinity and Polymer Adsorption.

Science.gov (United States)

Xie, Lei; Wang, Jingyi; Yuan, Duowei; Shi, Chen; Cui, Xin; Zhang, Hao; Liu, Qi; Liu, Qingxia; Zeng, Hongbo

2017-03-07

The surface characteristics of molybdenite (MoS 2 ) such as wettability and surface interactions have attracted much research interest in a wide range of engineering applications, such as froth flotation. In this work, a bubble probe atomic force microscope (AFM) technique was employed to directly measure the interaction forces between an air bubble and molybdenite mineral surface before/after polymer (i.e., guar gum) adsorption treatment. The AFM imaging showed that the polymer coverage on the surface of molybdenite could achieve ∼5.6, ∼44.5, and ∼100% after conditioning in 1, 5, and 10 ppm polymer solution, respectively, which coincided with the polymer coverage results based on contact angle measurements. The electrolyte concentration and surface treatment by polymer adsorption were found to significantly affect bubble-mineral interaction and attachment. The experimental force results on bubble-molybdenite (without polymer treatment) agreed well with the calculations using a theoretical model based on the Reynolds lubrication theory and augmented Young-Laplace equation including the effect of disjoining pressure. The overall surface repulsion was enhanced when the NaCl concentration decreased from 100 to 1 mM, which inhibited the bubble-molybdenite attachment. After conditioning the molybdenite surface in 1 ppm polymer solution, it was more difficult for air bubbles to attach to the molybdenite surface due to the weakened hydrophobic interaction with a shorter decay length. Increasing the polymer concentration to 5 ppm effectively inhibited bubble attachment on mineral surface, which was mainly due to the much reduced hydrophobic interaction as well as the additional steric repulsion between the extended polymer chains and bubble surface. The results provide quantitative information on the interaction mechanism between air bubbles and molybdenite mineral surfaces on the nanoscale, with useful implications for the development of effective polymer

Residues of 2, 4-D in air samples from Saskatchewan: 1966-1975.

Science.gov (United States)

Grover, R; Kerr, L A; Wallace, K; Yoshida, K; Maybank, J

1976-01-01

Residues of 2,4-D (2,4-dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966-68 and 1970-75 periods were determined by gas-liquid chromatographic techniques. Initially, individual esters of 2,4-D were characterized by retention times and confirmed further by co-injection and dual column procedures. Since 1973, however, only total 2,4-D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible. Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4-D, with butyl esters being found most frequently. The daily 24-hr mean atmospheric concentrations of 2,4-D ranged from 0.01 to 1.22 mug/m3, 0.01 to 13.50 mug/m3, and 0.05 to 0.59 mug/m3 for the iso-propyl, mixed butyl and iso-octyl esters, respectively. Even when the samples were analysed for the total 2,4-D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 mug/m3. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 mug/m3 of 2,4-D. In another 40% of the samples, the levels of 2,4-D ranged from 0.01 to 0.099 mug/m3. Only about 30% of the samples contained 2,4-D concentrations higher than 0.1 mug/m3, with only 10% or less exceeding 1 mug/m3. None of the samples, obtained with the high volume particulate sampler, showed any detectable levels of 2,4-D, indicating little or no transport of 2,4-D adsorbed on dust particles or as crystals of amine salts.

Sampling of power plant stacks for air toxic emissions: Final report for Phases 1 and 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-04-28

A test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPs) was conducted . Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical characterization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions. Field testing was conducted in two phases. The Phase I field program was performed over the period of August 24 through September 20, 1992, at the Tennessee Valley Authority Widows Creek Unit 8 Power Station, located near Stevenson (Jackson County), Alabama, on the Tennessee River. Sampling activities for Phase II were conducted from September 11 through October 14, 1993. Widows Creek Unit 8 is a 575-megawatt plant that uses bituminous coal averaging 3.7% sulfur and 13% ash. Downstream of the boiler, a venture wet scrubbing system is used for control of both sulfur dioxide and particulate emissions. There is no electrostatic precipitator (ESP) in this system. This system is atypical and represents only about 5% of the US utility industry. However, this site was chosen for this study because of the lack of information available for this particulate emission control system.

Air sampling to assess potential generation of aerosolized viable bacteria during flow cytometric analysis of unfixed bacterial suspensions

Science.gov (United States)

Carson, Christine F; Inglis, Timothy JJ

2018-01-01

This study investigated aerosolized viable bacteria in a university research laboratory during operation of an acoustic-assisted flow cytometer for antimicrobial susceptibility testing by sampling room air before, during and after flow cytometer use. The aim was to assess the risk associated with use of an acoustic-assisted flow cytometer analyzing unfixed bacterial suspensions. Air sampling in a nearby clinical laboratory was conducted during the same period to provide context for the existing background of microorganisms that would be detected in the air. The three species of bacteria undergoing analysis by flow cytometer in the research laboratory were Klebsiella pneumoniae, Burkholderia thailandensis and Streptococcus pneumoniae. None of these was detected from multiple 1000 L air samples acquired in the research laboratory environment. The main cultured bacteria in both locations were skin commensal and environmental bacteria, presumed to have been disturbed or dispersed in laboratory air by personnel movements during routine laboratory activities. The concentrations of bacteria detected in research laboratory air samples were reduced after interventional cleaning measures were introduced and were lower than those in the diagnostic clinical microbiology laboratory. We conclude that our flow cytometric analyses of unfixed suspensions of K. pneumoniae, B. thailandensis and S. pneumoniae do not pose a risk to cytometer operators or other personnel in the laboratory but caution against extrapolation of our results to other bacteria and/or different flow cytometric experimental procedures. PMID:29608197

Day and night variation in chemical composition and toxicological responses of size segregated urban air PM samples in a high air pollution situation

Science.gov (United States)

Jalava, P. I.; Wang, Q.; Kuuspalo, K.; Ruusunen, J.; Hao, L.; Fang, D.; Väisänen, O.; Ruuskanen, A.; Sippula, O.; Happo, M. S.; Uski, O.; Kasurinen, S.; Torvela, T.; Koponen, H.; Lehtinen, K. E. J.; Komppula, M.; Gu, C.; Jokiniemi, J.; Hirvonen, M.-R.

2015-11-01

Urban air particulate pollution is a known cause for adverse human health effects worldwide. China has encountered air quality problems in recent years due to rapid industrialization. Toxicological effects induced by particulate air pollution vary with particle sizes and season. However, it is not known how distinctively different photochemical activity and different emission sources during the day and the night affect the chemical composition of the PM size ranges and subsequently how it is reflected to the toxicological properties of the PM exposures. The particulate matter (PM) samples were collected in four different size ranges (PM10-2.5; PM2.5-1; PM1-0.2 and PM0.2) with a high volume cascade impactor. The PM samples were extracted with methanol, dried and thereafter used in the chemical and toxicological analyses. RAW264.7 macrophages were exposed to the particulate samples in four different doses for 24 h. Cytotoxicity, inflammatory parameters, cell cycle and genotoxicity were measured after exposure of the cells to particulate samples. Particles were characterized for their chemical composition, including ions, element and PAH compounds, and transmission electron microscopy (TEM) was used to take images of the PM samples. Chemical composition and the induced toxicological responses of the size segregated PM samples showed considerable size dependent differences as well as day to night variation. The PM10-2.5 and the PM0.2 samples had the highest inflammatory potency among the size ranges. Instead, almost all the PM samples were equally cytotoxic and only minor differences were seen in genotoxicity and cell cycle effects. Overall, the PM0.2 samples had the highest toxic potential among the different size ranges in many parameters. PAH compounds in the samples and were generally more abundant during the night than the day, indicating possible photo-oxidation of the PAH compounds due to solar radiation. This was reflected to different toxicity in the PM

Sampling Studies at an Air Force Live-Fire Bombing Range Impact Area

National Research Council Canada - National Science Library

Jenkins, Thomas F; Hewitt, Alan D; Ramsey, Charles A; Bjella, Kevin L; Bigl, Susan R; Lambert, Dennis J

2006-01-01

.... The main objective was to assess the effectiveness of using a systematic-random, multi-increment sampling strategy for the collection of representative surface soil samples in areas where bombing...

Slip length measurement of confined air flow on three smooth surfaces.

Science.gov (United States)

Pan, Yunlu; Bhushan, Bharat; Maali, Abdelhamid

2013-04-02

An experimental measurement of the slip length of air flow close to three different solid surfaces is presented. The substrate was driven by a nanopositioner moving toward an oscillating glass sphere glued to an atomic force microscopy (AFM) cantilever. A large separation distance was used to get more effective data. The slip length value was obtained by analyzing the amplitude and phase data of the cantilever. The measurements show that the slip length does not depend on the oscillation amplitude of the cantilever. Because of the small difference among the slip lengths of the three surfaces, a simplified analysis method was used. The results show that on glass, graphite, and mica surfaces the slip lengths are 98, 234, and 110 nm, respectively.

Ultrashort laser pulses and electromagnetic pulse generation in air and on dielectric surfaces

International Nuclear Information System (INIS)

Sprangle, P.; Penano, J.R.; Hafizi, B.; Kapetanakos, C.A.

2004-01-01

Intense, ultrashort laser pulses propagating in the atmosphere have been observed to emit sub-THz electromagnetic pulses (EMPS). The purpose of this paper is to analyze EMP generation from the interaction of ultrashort laser pulses with air and with dielectric surfaces and to determine the efficiency of conversion of laser energy to EMP energy. In our self-consistent model the laser pulse partially ionizes the medium, forms a plasma filament, and through the ponderomotive forces associated with the laser pulse, drives plasma currents which are the source of the EMP. The propagating laser pulse evolves under the influence of diffraction, Kerr focusing, plasma defocusing, and energy depletion due to electron collisions and ionization. Collective effects and recombination processes are also included in the model. The duration of the EMP in air, at a fixed point, is found to be a few hundred femtoseconds, i.e., on the order of the laser pulse duration plus the electron collision time. For steady state laser pulse propagation the flux of EMP energy is nonradiative and axially directed. Radiative EMP energy is present only for nonsteady state or transient laser pulse propagation. The analysis also considers the generation of EMP on the surface of a dielectric on which an ultrashort laser pulse is incident. For typical laser parameters, the power and energy conversion efficiency from laser radiation to EMP radiation in both air and from dielectric surfaces is found to be extremely small, -8 . Results of full-scale, self-consistent, numerical simulations of atmospheric and dielectric surface EMP generation are presented. A recent experiment on atmospheric EMP generation is also simulated

Adventitious Carbon on Primary Sample Containment Metal Surfaces

Science.gov (United States)

Calaway, M. J.; Fries, M. D.

2015-01-01

Future missions that return astromaterials with trace carbonaceous signatures will require strict protocols for reducing and controlling terrestrial carbon contamination. Adventitious carbon (AC) on primary sample containers and related hardware is an important source of that contamination. AC is a thin film layer or heterogeneously dispersed carbonaceous material that naturally accrues from the environment on the surface of atmospheric exposed metal parts. To test basic cleaning techniques for AC control, metal surfaces commonly used for flight hardware and curating astromaterials at JSC were cleaned using a basic cleaning protocol and characterized for AC residue. Two electropolished stainless steel 316L (SS- 316L) and two Al 6061 (Al-6061) test coupons (2.5 cm diameter by 0.3 cm thick) were subjected to precision cleaning in the JSC Genesis ISO class 4 cleanroom Precision Cleaning Laboratory. Afterwards, the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.

Water sampling device for detecting fuel failure

International Nuclear Information System (INIS)

Masubuchi, Yukio.

1997-01-01

A notched portion is formed at the lower end of an outer cap, and an extensible air bag is disposed being in contact with the inner side of the notched portion. A compressed air is sent into the outer gap through an air supply pipe to urge coolants thereby lowering the water level. A portion of the compressed air gets out of the outer gap from the notched portion, and if air bubbles are observed on the surface of coolants in a pressure vessel of a reactor, the outer cap is confirmed to be attached to the upper lattice plate. Compressed air is supplied to the air bag to close the notched portion. Then, coolants are sucked from a water level confirmation pipe. The level of coolants is further lowered, and the compressed air is sucked from the water level confirmation pipe instead of the coolants. Then, the level of the coolants at the inner side of the inner cap is confirmed to be made lower than the upper end of the channel box of a reactor fuel assembly. Then, coolants in the channel box are sampled, as a specimen water, through a water sampling pipe. (I.N.)

The air bubble entrapped under a drop impacting on a solid surface

Science.gov (United States)

Thoroddsen, S. T.; Etoh, T. G.; Takehara, K.; Ootsuka, N.; Hatsuki, Y.

2005-12-01

We present experimental observations of the disk of air caught under a drop impacting onto a solid surface. By imaging the impact through an acrylic plate with an ultra-high-speed video camera, we can follow the evolution of the air disk as it contracts into a bubble under the centre of the drop. The initial size and contraction speed of the disk were measured for a range of impact Weber and Reynolds numbers. The size of the initial disk is related to the bottom curvature of the drop at the initial contact, as measured in free-fall. The initial contact often leaves behind a ring of micro-bubbles, marking its location. The air disk contracts at a speed comparable to the corresponding air disks caught under a drop impacting onto a liquid surface. This speed also seems independent of the wettability of the liquid, which only affects the azimuthal shape of the contact line. For some impact conditions, the dynamics of the contraction leaves a small droplet at the centre of the bubble. This arises from a capillary wave propagating from the edges of the contracting disk towards the centre. As the wave converges its amplitude grows until it touches the solid substrate, thereby pinching off the micro-droplet at the plate, in the centre of the bubble. The effect of increasing liquid viscosity is to slow down the contraction speed and to produce a more irregular contact line leaving more micro-bubbles along the initial ring.

Passive air sampling for persistent organic pollutants: Introductory remarks to the special issue

International Nuclear Information System (INIS)

Harner, Tom; Bartkow, Michael; Holoubek, Ivan; Klanova, Jana; Wania, Frank; Gioia, Rosalinda; Moeckel, Claudia; Sweetman, Andrew J.; Jones, Kevin C.

2006-01-01

There have been a number of developments in the need, design and use of passive air samplers (PAS) for persistent organic pollutants (POPs). This article is the first in a Special Issue of the journal to review these developments and some of the data arising from them. We explain the need and benefit of developing PAS for POPs, the different approaches that can be used, and highlight future developments and needs. - The context, needs and state-of-the-art of passive air sampling techniques for atmospheric persistent organic pollutants are discussed

The diversity and distribution of fungi on residential surfaces.

Directory of Open Access Journals (Sweden)

Rachel I Adams

Full Text Available The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. "Weedy" genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents' foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea. Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear - to varying degrees - to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins

Recent Improvements in Retrieving Near-Surface Air Temperature and Humidity Using Microwave Remote Sensing

Science.gov (United States)

Roberts, J. Brent

2010-01-01

Detailed studies of the energy and water cycles require accurate estimation of the turbulent fluxes of moisture and heat across the atmosphere-ocean interface at regional to basin scale. Providing estimates of these latent and sensible heat fluxes over the global ocean necessitates the use of satellite or reanalysis-based estimates of near surface variables. Recent studies have shown that errors in the surface (10 meter)estimates of humidity and temperature are currently the largest sources of uncertainty in the production of turbulent fluxes from satellite observations. Therefore, emphasis has been placed on reducing the systematic errors in the retrieval of these parameters from microwave radiometers. This study discusses recent improvements in the retrieval of air temperature and humidity through improvements in the choice of algorithms (linear vs. nonlinear) and the choice of microwave sensors. Particular focus is placed on improvements using a neural network approach with a single sensor (Special Sensor Microwave/Imager) and the use of combined sensors from the NASA AQUA satellite platform. The latter algorithm utilizes the unique sampling available on AQUA from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A). Current estimates of uncertainty in the near-surface humidity and temperature from single and multi-sensor approaches are discussed and used to estimate errors in the turbulent fluxes.

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

An Intrinsic Algorithm for Parallel Poisson Disk Sampling on Arbitrary Surfaces.

Science.gov (United States)

Ying, Xiang; Xin, Shi-Qing; Sun, Qian; He, Ying

2013-03-08

Poisson disk sampling plays an important role in a variety of visual computing, due to its useful statistical property in distribution and the absence of aliasing artifacts. While many effective techniques have been proposed to generate Poisson disk distribution in Euclidean space, relatively few work has been reported to the surface counterpart. This paper presents an intrinsic algorithm for parallel Poisson disk sampling on arbitrary surfaces. We propose a new technique for parallelizing the dart throwing. Rather than the conventional approaches that explicitly partition the spatial domain to generate the samples in parallel, our approach assigns each sample candidate a random and unique priority that is unbiased with regard to the distribution. Hence, multiple threads can process the candidates simultaneously and resolve conflicts by checking the given priority values. It is worth noting that our algorithm is accurate as the generated Poisson disks are uniformly and randomly distributed without bias. Our method is intrinsic in that all the computations are based on the intrinsic metric and are independent of the embedding space. This intrinsic feature allows us to generate Poisson disk distributions on arbitrary surfaces. Furthermore, by manipulating the spatially varying density function, we can obtain adaptive sampling easily.

Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings.

Science.gov (United States)

Normand, Anne-Cécile; Ranque, Stéphane; Cassagne, Carole; Gaudart, Jean; Sallah, Kankoé; Charpin, Denis-André; Piarroux, Renaud

2016-03-01

Many ailments can be linked to exposure to indoor airborne fungus. However, obtaining a precise measurement of airborne fungal levels is complicated partly due to indoor air fluctuations and non-standardized techniques. Electrostatic dust collector (EDC) sampling devices have been used to measure a wide range of airborne analytes, including endotoxins, allergens, β-glucans, and microbial DNA in various indoor environments. In contrast, viable mold contamination has only been assessed in highly contaminated environments such as farms and archive buildings. This study aimed to assess the use of EDCs, compared with repeated air-impactor measurements, to assess airborne viable fungal flora in moderately contaminated indoor environments. Indoor airborne fungal flora was cultured from EDCs and daily air-impaction samples collected in an office building and a daycare center. The quantitative fungal measurements obtained using a single EDC significantly correlated with the cumulative measurement of nine daily air impactions. Both methods enabled the assessment of fungal exposure, although a few differences were observed between the detected fungal species and the relative quantity of each species. EDCs were also used over a 32-month period to monitor indoor airborne fungal flora in a hospital office building, which enabled us to assess the impact of outdoor events (e.g. ground excavations) on the fungal flora levels on the indoor environment. In conclusion, EDC-based measurements provided a relatively accurate profile of the viable airborne flora present during a sampling period. In particular, EDCs provided a more representative assessment of fungal levels compared with single air-impactor sampling. The EDC technique is also simpler than performing repetitive air-impaction measures over the course of several consecutive days. EDC is a versatile tool for collecting airborne samples and was efficient for measuring mold levels in indoor environments. © The Author 2015

Portable monitors for measuring radon and its progenies air by intergrated sampling method

International Nuclear Information System (INIS)

Zhang Huaiqin; Su Jingling; Yao Wanyuan; Liu Jinhua

1989-01-01

Two kinds of portable monitors have been developed, which can be used to measure the concentration of radon or potential energy concentration of radon or potential energy concentration of radon progenies in air. The thermoluminescent material CaSO 4 (Tm) is used as a detecting element for both of them. The lowest detectable limit of the passive radon monitor is about 1.5 Bq/m 3 for radon in air, as the exposure time being one week. Its main advantages are high reliability and convenient manipulation. The working level monitor for radon progenies in air consists of a mini membrane pump and an integrating probe. The lowest detectable limit is about 6.2 x 10 -9 J/m 3 , as the sampling time being 6 hours. It weights only about 0.35 kg

Centrifugal Compressor Surge Margin Improved With Diffuser Hub Surface Air Injection

Science.gov (United States)

Skoch, Gary J.

2002-01-01

Aerodynamic stability is an important parameter in the design of compressors for aircraft gas turbine engines. Compression system instabilities can cause compressor surge, which may lead to the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. The margin of safety is typically referred to as "surge margin." Achieving the highest possible level of surge margin while meeting design point performance objectives is the goal of the compressor designer. However, performance goals often must be compromised in order to achieve adequate levels of surge margin. Techniques to improve surge margin will permit more aggressive compressor designs. Centrifugal compressor surge margin improvement was demonstrated at the NASA Glenn Research Center by injecting air into the vaned diffuser of a 4:1-pressure-ratio centrifugal compressor. Tests were performed using injector nozzles located on the diffuser hub surface of a vane-island diffuser in the vaneless region between the impeller trailing edge and the diffuser-vane leading edge. The nozzle flow path and discharge shape were designed to produce an air stream that remained tangent to the hub surface as it traveled into the diffuser passage. Injector nozzles were located near the leading edge of 23 of the 24 diffuser vanes. One passage did not contain an injector so that instrumentation located in that passage would be preserved. Several orientations of the injected stream relative to the diffuser vane leading edge were tested over a range of injected flow rates. Only steady flow (nonpulsed) air injection was tested. At 100 percent of the design speed, a 15-percent improvement in the baseline surge margin was achieved with a nozzle orientation that produced a jet that was bisected by the diffuser vane leading edge. Other orientations also improved the baseline surge margin. Tests were conducted at speeds below the

Comparison of Passive and Active Air Sampling (PAAS) Methods for PCBs – A Pilot Study in New York City Schools

Science.gov (United States)

PCBs were used extensively in school building materials (caulk and lighting fixture ballasts) during the approximate period of 1950-1978. Most of the schools built nationwide during this period have not had indoor air sampling conducted for PCBs. Passive air sampling holds promi...

Potential contamination of shipboard air samples by diffusive emissions of PCBs and other organic pollutants: implications and solutions.

Science.gov (United States)

Lohmann, Rainer; Jaward, Foday M; Durham, Louise; Barber, Jonathan L; Ockenden, Wendy; Jones, Kevin C; Bruhn, Regina; Lakaschus, Soenke; Dachs, Jordi; Booij, Kees

2004-07-15

Air samples were taken onboard the RRS Bransfield on an Atlantic cruise from the United Kingdom to Halley, Antarctica, from October to December 1998, with the aim of establishing PCB oceanic background air concentrations and assessing their latitudinal distribution. Great care was taken to minimize pre- and post-collection contamination of the samples, which was validated through stringent QA/QC procedures. However, there is evidence that onboard contamination of the air samples occurred,following insidious, diffusive emissions on the ship. Other data (for PCBs and other persistent organic pollutants (POPs)) and examples of shipboard contamination are presented. The implications of these findings for past and future studies of global POPs distribution are discussed. Recommendations are made to help critically appraise and minimize the problems of insidious/diffusive shipboard contamination.

A new sampling technique for surface exposure dating using a portable electric rock cutter

Directory of Open Access Journals (Sweden)

Yusuke Suganuma

2012-07-01

Full Text Available Surface exposure dating using in situ cosmogenic nuclides has contributed to our understanding of Earth-surface processes. The precision of the ages estimated by this method is affected by the sample geometry; therefore, high accuracy measurements of the thickness and shape of the rock sample (thickness and shape is crucial. However, it is sometimes diffi cult to meet these requirements by conventional sampling methods with a hammer and chisel. Here, we propose a new sampling technique using a portable electric rock cutter. This sampling technique is faster, produces more precisely shaped samples, and allows for a more precise age interpretation. A simple theoretical modeldemonstrates that the age error due to defective sample geometry increases as the total sample thickness increases, indicating the importance of precise sampling for surface exposure dating.

New Technology-Large-Area Three- Dimensional Surface Profiling Using Only Focused Air-Coupled Ultrasound-Given 1999 R&D 100 Award

Science.gov (United States)

Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

2000-01-01

Surface topography, which significantly affects the performance of many industrial components, is normally measured with diamond-tip profilometry over small areas or with optical scattering methods over larger areas. To develop air-coupled surface profilometry, the NASA Glenn Research Center at Lewis Field initiated a Space Act Agreement with Sonix, Inc., through two Glenn programs, the Advanced High Temperature Engine Materials Program (HITEMP) and COMMTECH. The work resulted in quantitative surface topography profiles obtained using only high-frequency, focused ultrasonic pulses in air. The method is nondestructive, noninvasive, and noncontact, and it does not require light-reflective surfaces. Air surface profiling may be desirable when diamond-tip or laserbased methods are impractical, such as over large areas, when a significant depth range is required, or for curved surfaces. When the configuration is optimized, the method is reasonably rapid and all the quantitative analysis facilities are online, including two- and three-dimensional visualization, extreme value filtering (for faulty data), and leveling.

Filamentary superhydrophobic Teflon surfaces: Moderate apparent contact angle but superior air-retaining properties.

Science.gov (United States)

Di Mundo, Rosa; Bottiglione, Francesco; Palumbo, Fabio; Notarnicola, Michele; Carbone, Giuseppe

2016-11-15

Micro-scale textured Teflon surfaces, resulting from plasma etching modification, show extremely high water contact angle values and fairly good resistance to water penetration when hit by water drops at medium-high speed. This behavior is more pronounced when these surfaces present denser and smaller micrometric reliefs. Tailoring the top of these reliefs with a structure which further stabilizes the air may further increase resistance to wetting (water penetration) under static and dynamic conditions. Conditions of the oxygen fed plasma were tuned in order to explore the possibility of obtaining differently topped structures on the surface of the polymer. Scanning Electron Microscopy (SEM) was used to explore topography and X-ray Photoelectron Spectroscopy (XPS) to assess chemical similarity of the modified surfaces. Beside the usual advancing and receding water contact angle (WCA) measurements, surfaces were subjected to high speed impacting drops and immersion in water. At milder, i.e. shorter time and lower input power, plasma conditions formation of peculiar filaments is observed on the top of the sculpted reliefs. Filamentary topped surfaces result in a lower WCA than the spherical ones, appearing in this sense less superhydrophobic. However, these surfaces give rise to the formation of a more pronounced air layer when placed underwater. Further, when hit by water drops falling at medium/high speed, they show a higher resistance to water penetration and a sensitively lower surface-liquid contact time. The contact time is as low as previously observed only on heated solids. This behavior may be ascribed to the cavities formed beneath the filaments which, similarly with the salvinia leaf structures, require a surplus of pressure to be filled by water. Also, it suggests a different concept of superhydrophobicity, which cannot be expected on the basis of the conventional water contact angle characterization. Copyright © 2016 Elsevier Inc. All rights reserved.

Compressed-air power tools in orthopaedic surgery: exhaust air is a potential source of contamination.

Science.gov (United States)

Sagi, H C; DiPasquale, Thomas; Sanders, Roy; Herscovici, Dolfi

2002-01-01

To determine if the exhaust from surgical compressed-air power tools contains bacteria and if the exhaust leads to contamination of sterile surfaces. Bacteriologic study of orthopaedic power tools. Level I trauma center operative theater. None. Part I. Exhaust from two sterile compact air drills was sampled directly at the exhaust port. Part II. Exhaust from the drills was directed at sterile agar plates from varying distances. The agar plates represented sterile surfaces within the operative field. Part III. Control cultures. A battery-powered drill was operated over open agar plates in similar fashion as the compressed-air drills. Agar plates left open in the operative theater served as controls to rule out atmospheric contamination. Random cultures were taken from agar plates, gloves, drills, and hoses. Incidence of positive cultures. In Part I, all filters from both compressed-air drill exhausts were culture negative ( = 0.008). In Part II, the incidence of positive cultures for air drills number one and number two was 73% and 82%, respectively. The most commonly encountered organisms were, coagulase-negative Staphylococcus, and Micrococcus species. All control cultures from agar plates, battery-powered drill, gloves, and hoses were negative ( compressed-air power tools in orthopaedic surgery may contribute to the dissemination of bacteria onto the surgical field. We do not recommend the use of compressed-air power tools that do not have a contained exhaust.

Surface Environmental Surveillance Project: Locations Manual Volume 1 – Air and Water Volume 2 – Farm Products, Soil & Vegetation, and Wildlife

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